Add or subtract time from the Hardware Clock to account for systematic drift since the last time the clock was set or adjusted. See the discussion below, under *The Adjust Function*.
*--getepoch*; *--setepoch*::
- These functions are for Alpha machines only, and are only available through the Linux kernel RTC driver. +
- {nbsp} +
- They are used to read and set the kernel's Hardware Clock epoch value. Epoch is the number of years into AD to which a zero year value in the Hardware Clock refers. For example, if the machine's BIOS sets the year counter in the Hardware Clock to contain the number of full years since 1952, then the kernel's Hardware Clock epoch value must be 1952. +
- {nbsp} +
- The *--setepoch* function requires using the *--epoch* option to specify the year. For example: +
- {nbsp} +
- **hwclock --setepoch --epoch=1952** +
- {nbsp} +
- The RTC driver attempts to guess the correct epoch value, so setting it may not be required. +
- {nbsp} +
- This epoch value is used whenever *hwclock* reads or sets the Hardware Clock on an Alpha machine. For ISA machines the kernel uses the fixed Hardware Clock epoch of 1900.
+These functions are for Alpha machines only, and are only available through the Linux kernel RTC driver.
++
+They are used to read and set the kernel's Hardware Clock epoch value. Epoch is the number of years into AD to which a zero year value in the Hardware Clock refers. For example, if the machine's BIOS sets the year counter in the Hardware Clock to contain the number of full years since 1952, then the kernel's Hardware Clock epoch value must be 1952.
++
+The *--setepoch* function requires using the *--epoch* option to specify the year. For example:
++
+**hwclock --setepoch --epoch=1952**
++
+The RTC driver attempts to guess the correct epoch value, so setting it may not be required.
++
+This epoch value is used whenever *hwclock* reads or sets the Hardware Clock on an Alpha machine. For ISA machines the kernel uses the fixed Hardware Clock epoch of 1900.
*--predict*::
- Predict what the Hardware Clock will read in the future based upon the time given by the *--date* option and the information in _{ADJTIME_PATH}_. This is useful, for example, to account for drift when setting a Hardware Clock wakeup (aka alarm). See *rtcwake*(8). +
- {nbsp} +
- Do not use this function if the Hardware Clock is being modified by anything other than the current operating system's *hwclock* command, such as '11 minute mode' or from dual-booting another OS.
+Predict what the Hardware Clock will read in the future based upon the time given by the *--date* option and the information in _{ADJTIME_PATH}_. This is useful, for example, to account for drift when setting a Hardware Clock wakeup (aka alarm). See *rtcwake*(8).
++
+Do not use this function if the Hardware Clock is being modified by anything other than the current operating system's *hwclock* command, such as '11 minute mode' or from dual-booting another OS.
*-r*, *--show*; *--get*::
- Read the Hardware Clock and print its time to standard output in the *ISO 8601* format. The time shown is always in local time, even if you keep your Hardware Clock in UTC. See the *--localtime* option. +
- {nbsp} +
- Showing the Hardware Clock time is the default when no function is specified. +
- {nbsp} +
- The *--get* function also applies drift correction to the time read, based upon the information in _{ADJTIME_PATH}_. Do not use this function if the Hardware Clock is being modified by anything other than the current operating system's *hwclock* command, such as '11 minute mode' or from dual-booting another OS.
+Read the Hardware Clock and print its time to standard output in the *ISO 8601* format. The time shown is always in local time, even if you keep your Hardware Clock in UTC. See the *--localtime* option.
++
+Showing the Hardware Clock time is the default when no function is specified.
++
+The *--get* function also applies drift correction to the time read, based upon the information in _{ADJTIME_PATH}_. Do not use this function if the Hardware Clock is being modified by anything other than the current operating system's *hwclock* command, such as '11 minute mode' or from dual-booting another OS.
*-s*, *--hctosys*::
- Set the System Clock from the Hardware Clock. The time read from the Hardware Clock is compensated to account for systematic drift before using it to set the System Clock. See the discussion below, under *The Adjust Function*. +
- {nbsp} +
- The System Clock must be kept in the UTC timescale for date-time applications to work correctly in conjunction with the timezone configured for the system. If the Hardware Clock is kept in local time then the time read from it must be shifted to the UTC timescale before using it to set the System Clock. The *--hctosys* function does this based upon the information in the _{ADJTIME_PATH}_ file or the command line arguments *--localtime* and *--utc*. Note: no daylight saving adjustment is made. See the discussion below, under *LOCAL vs UTC*. +
- {nbsp} +
- The kernel also keeps a timezone value, the *--hctosys* function sets it to the timezone configured for the system. The system timezone is configured by the TZ environment variable or the _/etc/localtime_ file, as *tzset*(3) would interpret them. The obsolete _tz_dsttime_ field of the kernel's timezone value is set to zero. (For details on what this field used to mean, see *settimeofday*(2).) +
- {nbsp} +
- When used in a startup script, making the *--hctosys* function the first caller of *settimeofday*(2) from boot, it will set the NTP '11 minute mode' timescale via the _persistent_clock_is_local_ kernel variable. If the Hardware Clock's timescale configuration is changed then a reboot is required to inform the kernel. See the discussion below, under *Automatic Hardware Clock Synchronization by the Kernel*. +
- {nbsp} +
- This is a good function to use in one of the system startup scripts before the file systems are mounted read/write. +
- {nbsp} +
- This function should never be used on a running system. Jumping system time will cause problems, such as corrupted filesystem timestamps. Also, if something has changed the Hardware Clock, like NTP's '11 minute mode', then *--hctosys* will set the time incorrectly by including drift compensation. +
- {nbsp} +
- Drift compensation can be inhibited by setting the drift factor in _{ADJTIME_PATH}_ to zero. This setting will be persistent as long as the *--update-drift* option is not used with *--systohc* at shutdown (or anywhere else). Another way to inhibit this is by using the *--noadjfile* option when calling the *--hctosys* function. A third method is to delete the _{ADJTIME_PATH}_ file. *Hwclock* will then default to using the UTC timescale for the Hardware Clock. If the Hardware Clock is ticking local time it will need to be defined in the file. This can be done by calling *hwclock --localtime --adjust*; when the file is not present this command will not actually adjust the Clock, but it will create the file with local time configured, and a drift factor of zero. +
- {nbsp} +
- A condition under which inhibiting *hwclock*'s drift correction may be desired is when dual-booting multiple operating systems. If while this instance of Linux is stopped, another OS changes the Hardware Clock's value, then when this instance is started again the drift correction applied will be incorrect. +
- {nbsp} +
- For *hwclock*'s drift correction to work properly it is imperative that nothing changes the Hardware Clock while its Linux instance is not running.
+Set the System Clock from the Hardware Clock. The time read from the Hardware Clock is compensated to account for systematic drift before using it to set the System Clock. See the discussion below, under *The Adjust Function*.
++
+The System Clock must be kept in the UTC timescale for date-time applications to work correctly in conjunction with the timezone configured for the system. If the Hardware Clock is kept in local time then the time read from it must be shifted to the UTC timescale before using it to set the System Clock. The *--hctosys* function does this based upon the information in the _{ADJTIME_PATH}_ file or the command line arguments *--localtime* and *--utc*. Note: no daylight saving adjustment is made. See the discussion below, under *LOCAL vs UTC*.
++
+The kernel also keeps a timezone value, the *--hctosys* function sets it to the timezone configured for the system. The system timezone is configured by the TZ environment variable or the _/etc/localtime_ file, as *tzset*(3) would interpret them. The obsolete _tz_dsttime_ field of the kernel's timezone value is set to zero. (For details on what this field used to mean, see *settimeofday*(2).)
++
+When used in a startup script, making the *--hctosys* function the first caller of *settimeofday*(2) from boot, it will set the NTP '11 minute mode' timescale via the _persistent_clock_is_local_ kernel variable. If the Hardware Clock's timescale configuration is changed then a reboot is required to inform the kernel. See the discussion below, under *Automatic Hardware Clock Synchronization by the Kernel*.
++
+This is a good function to use in one of the system startup scripts before the file systems are mounted read/write.
++
+This function should never be used on a running system. Jumping system time will cause problems, such as corrupted filesystem timestamps. Also, if something has changed the Hardware Clock, like NTP's '11 minute mode', then *--hctosys* will set the time incorrectly by including drift compensation.
++
+Drift compensation can be inhibited by setting the drift factor in _{ADJTIME_PATH}_ to zero. This setting will be persistent as long as the *--update-drift* option is not used with *--systohc* at shutdown (or anywhere else). Another way to inhibit this is by using the *--noadjfile* option when calling the *--hctosys* function. A third method is to delete the _{ADJTIME_PATH}_ file. *Hwclock* will then default to using the UTC timescale for the Hardware Clock. If the Hardware Clock is ticking local time it will need to be defined in the file. This can be done by calling *hwclock --localtime --adjust*; when the file is not present this command will not actually adjust the Clock, but it will create the file with local time configured, and a drift factor of zero.
++
+A condition under which inhibiting *hwclock*'s drift correction may be desired is when dual-booting multiple operating systems. If while this instance of Linux is stopped, another OS changes the Hardware Clock's value, then when this instance is started again the drift correction applied will be incorrect.
++
+For *hwclock*'s drift correction to work properly it is imperative that nothing changes the Hardware Clock while its Linux instance is not running.
*--set*::
- Set the Hardware Clock to the time given by the *--date* option, and update the timestamps in _{ADJTIME_PATH}_. With the *--update-drift* option also (re)calculate the drift factor. Try it without the option if *--set* fails. See *--update-drift* below.
+Set the Hardware Clock to the time given by the *--date* option, and update the timestamps in _{ADJTIME_PATH}_. With the *--update-drift* option also (re)calculate the drift factor. Try it without the option if *--set* fails. See *--update-drift* below.
*--systz*::
- This is an alternate to the *--hctosys* function that does not read the Hardware Clock nor set the System Clock; consequently there is not any drift correction. It is intended to be used in a startup script on systems with kernels above version 2.6 where you know the System Clock has been set from the Hardware Clock by the kernel during boot. +
- {nbsp} +
- It does the following things that are detailed above in the *--hctosys* function: +
- {nbsp} +
- * Corrects the System Clock timescale to UTC as needed. Only instead of accomplishing this by setting the System Clock, *hwclock* simply informs the kernel and it handles the change.
- * Sets the kernel's NTP '11 minute mode' timescale.
- * Sets the kernel's timezone. +
- {nbsp} +
- The first two are only available on the first call of *settimeofday*(2) after boot. Consequently this option only makes sense when used in a startup script. If the Hardware Clocks timescale configuration is changed then a reboot would be required to inform the kernel.
+This is an alternate to the *--hctosys* function that does not read the Hardware Clock nor set the System Clock; consequently there is not any drift correction. It is intended to be used in a startup script on systems with kernels above version 2.6 where you know the System Clock has been set from the Hardware Clock by the kernel during boot.
++
+It does the following things that are detailed above in the *--hctosys* function:
+
+* Corrects the System Clock timescale to UTC as needed. Only instead of accomplishing this by setting the System Clock, *hwclock* simply informs the kernel and it handles the change.
+* Sets the kernel's NTP '11 minute mode' timescale.
+* Sets the kernel's timezone.
+
+The first two are only available on the first call of *settimeofday*(2) after boot. Consequently this option only makes sense when used in a startup script. If the Hardware Clocks timescale configuration is changed then a reboot would be required to inform the kernel.
*-w*, *--systohc*::
- Set the Hardware Clock from the System Clock, and update the timestamps in _{ADJTIME_PATH}_. With the *--update-drift* option also (re)calculate the drift factor. Try it without the option if *--systohc* fails. See *--update-drift* below.
+Set the Hardware Clock from the System Clock, and update the timestamps in _{ADJTIME_PATH}_. With the *--update-drift* option also (re)calculate the drift factor. Try it without the option if *--systohc* fails. See *--update-drift* below.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== OPTIONS
**--adjfile=**__filename__::
- Override the default _{ADJTIME_PATH}_ file path.
+Override the default _{ADJTIME_PATH}_ file path.
**--date=**__date_string__::
- This option must be used with the *--set* or *--predict* functions, otherwise it is ignored. +
- {nbsp} +
- *hwclock --set --date='16:45'* +
- *hwclock --predict --date='2525-08-14 07:11:05'* +
- {nbsp} +
- The argument must be in local time, even if you keep your Hardware Clock in UTC. See the *--localtime* option. Therefore, the argument should not include any timezone information. It also should not be a relative time like "+5 minutes", because *hwclock*'s precision depends upon correlation between the argument's value and when the enter key is pressed. Fractional seconds are silently dropped. This option is capable of understanding many time and date formats, but the previous parameters should be observed.
+This option must be used with the *--set* or *--predict* functions, otherwise it is ignored.
++
+*hwclock --set --date='16:45'*
++
+*hwclock --predict --date='2525-08-14 07:11:05'*
++
+The argument must be in local time, even if you keep your Hardware Clock in UTC. See the *--localtime* option. Therefore, the argument should not include any timezone information. It also should not be a relative time like "+5 minutes", because *hwclock*'s precision depends upon correlation between the argument's value and when the enter key is pressed. Fractional seconds are silently dropped. This option is capable of understanding many time and date formats, but the previous parameters should be observed.
**--delay=**__seconds__::
- This option can be used to overwrite the internally used delay when setting the clock time. The default is 0.5 (500ms) for rtc_cmos, for another RTC types the delay is 0. If RTC type is impossible to determine (from sysfs) then it defaults also to 0.5 to be backwardly compatible. +
- {nbsp} +
- The 500ms default is based on commonly used MC146818A-compatible (x86) hardware clock. This Hardware Clock can only be set to any integer time plus one half second. The integer time is required because there is no interface to set or get a fractional second. The additional half second delay is because the Hardware Clock updates to the following second precisely 500 ms after setting the new time. Unfortunately, this behavior is hardware specific and in same cases another delay is required.
+This option can be used to overwrite the internally used delay when setting the clock time. The default is 0.5 (500ms) for rtc_cmos, for another RTC types the delay is 0. If RTC type is impossible to determine (from sysfs) then it defaults also to 0.5 to be backwardly compatible.
++
+The 500ms default is based on commonly used MC146818A-compatible (x86) hardware clock. This Hardware Clock can only be set to any integer time plus one half second. The integer time is required because there is no interface to set or get a fractional second. The additional half second delay is because the Hardware Clock updates to the following second precisely 500 ms after setting the new time. Unfortunately, this behavior is hardware specific and in same cases another delay is required.
*-D*, *--debug*::
- Use *--verbose*. The *--debug* option has been deprecated and may be repurposed or removed in a future release.
+Use *--verbose*. The *--debug* option has been deprecated and may be repurposed or removed in a future release.
*--directisa*::
- This option is meaningful for ISA compatible machines in the x86 and x86_64 family. For other machines, it has no effect. This option tells *hwclock* to use explicit I/O instructions to access the Hardware Clock. Without this option, *hwclock* will use the rtc device file, which it assumes to be driven by the Linux RTC device driver. As of v2.26 it will no longer automatically use directisa when the rtc driver is unavailable; this was causing an unsafe condition that could allow two processes to access the Hardware Clock at the same time. Direct hardware access from userspace should only be used for testing, troubleshooting, and as a last resort when all other methods fail. See the *--rtc* option.
+This option is meaningful for ISA compatible machines in the x86 and x86_64 family. For other machines, it has no effect. This option tells *hwclock* to use explicit I/O instructions to access the Hardware Clock. Without this option, *hwclock* will use the rtc device file, which it assumes to be driven by the Linux RTC device driver. As of v2.26 it will no longer automatically use directisa when the rtc driver is unavailable; this was causing an unsafe condition that could allow two processes to access the Hardware Clock at the same time. Direct hardware access from userspace should only be used for testing, troubleshooting, and as a last resort when all other methods fail. See the *--rtc* option.
**--epoch=**__year__::
- This option is required when using the *--setepoch* function. The minimum _year_ value is 1900. The maximum is system dependent (*ULONG_MAX - 1*).
+This option is required when using the *--setepoch* function. The minimum _year_ value is 1900. The maximum is system dependent (*ULONG_MAX - 1*).
*-f*, **--rtc=**__filename__::
- Override *hwclock*'s default rtc device file name. Otherwise it will use the first one found in this order: _/dev/rtc0_ _/dev/rtc_ _/dev/misc/rtc_ For *IA-64:* _/dev/efirtc_ _/dev/misc/efirtc_
+Override *hwclock*'s default rtc device file name. Otherwise it will use the first one found in this order: _/dev/rtc0_, _/dev/rtc_, _/dev/misc/rtc_. For *IA-64:* _/dev/efirtc_ _/dev/misc/efirtc_
*-l*, *--localtime*; *-u*, *--utc*::
- Indicate which timescale the Hardware Clock is set to. +
- {nbsp} +
- The Hardware Clock may be configured to use either the UTC or the local timescale, but nothing in the clock itself says which alternative is being used. The *--localtime* or *--utc* options give this information to the *hwclock* command. If you specify the wrong one (or specify neither and take a wrong default), both setting and reading the Hardware Clock will be incorrect. +
- {nbsp} +
- If you specify neither *--utc* nor *--localtime* then the one last given with a set function (*--set*, *--systohc*, or *--adjust*), as recorded in _{ADJTIME_PATH}_, will be used. If the adjtime file doesn't exist, the default is UTC. +
- {nbsp} +
- Note: daylight saving time changes may be inconsistent when the Hardware Clock is kept in local time. See the discussion below, under *LOCAL vs UTC*.
+Indicate which timescale the Hardware Clock is set to.
++
+The Hardware Clock may be configured to use either the UTC or the local timescale, but nothing in the clock itself says which alternative is being used. The *--localtime* or *--utc* options give this information to the *hwclock* command. If you specify the wrong one (or specify neither and take a wrong default), both setting and reading the Hardware Clock will be incorrect.
++
+If you specify neither *--utc* nor *--localtime* then the one last given with a set function (*--set*, *--systohc*, or *--adjust*), as recorded in _{ADJTIME_PATH}_, will be used. If the adjtime file doesn't exist, the default is UTC.
++
+Note: daylight saving time changes may be inconsistent when the Hardware Clock is kept in local time. See the discussion below, under *LOCAL vs UTC*.
*--noadjfile*::
- Disable the facilities provided by _{ADJTIME_PATH}_. *hwclock* will not read nor write to that file with this option. Either *--utc* or *--localtime* must be specified when using this option.
+Disable the facilities provided by _{ADJTIME_PATH}_. *hwclock* will not read nor write to that file with this option. Either *--utc* or *--localtime* must be specified when using this option.
*--test*::
- Do not actually change anything on the system, that is, the Clocks or _{ADJTIME_PATH}_ (*--verbose* is implicit with this option).
+Do not actually change anything on the system, that is, the Clocks or _{ADJTIME_PATH}_ (*--verbose* is implicit with this option).
*--update-drift*::
- Update the Hardware Clock's drift factor in _{ADJTIME_PATH}_. It can only be used with *--set* or *--systohc*. +
- {nbsp} +
- A minimum four hour period between settings is required. This is to avoid invalid calculations. The longer the period, the more precise the resulting drift factor will be. +
- {nbsp} +
- This option was added in v2.26, because it is typical for systems to call *hwclock --systohc* at shutdown; with the old behaviour this would automatically (re)calculate the drift factor which caused several problems: +
- {nbsp} +
- * When using NTP with an '11 minute mode' kernel the drift factor would be clobbered to near zero.
- * It would not allow the use of 'cold' drift correction. With most configurations using 'cold' drift will yield favorable results. Cold, means when the machine is turned off which can have a significant impact on the drift factor.
- * (Re)calculating drift factor on every shutdown delivers suboptimal results. For example, if ephemeral conditions cause the machine to be abnormally hot the drift factor calculation would be out of range.
- * Significantly increased system shutdown times (as of v2.31 when not using *--update-drift* the RTC is not read).
+Update the Hardware Clock's drift factor in _{ADJTIME_PATH}_. It can only be used with *--set* or *--systohc*.
++
+A minimum four hour period between settings is required. This is to avoid invalid calculations. The longer the period, the more precise the resulting drift factor will be.
++
+This option was added in v2.26, because it is typical for systems to call *hwclock --systohc* at shutdown; with the old behaviour this would automatically (re)calculate the drift factor which caused several problems:
++
+* When using NTP with an '11 minute mode' kernel the drift factor would be clobbered to near zero.
+* It would not allow the use of 'cold' drift correction. With most configurations using 'cold' drift will yield favorable results. Cold, means when the machine is turned off which can have a significant impact on the drift factor.
+* (Re)calculating drift factor on every shutdown delivers suboptimal results. For example, if ephemeral conditions cause the machine to be abnormally hot the drift factor calculation would be out of range.
+* Significantly increased system shutdown times (as of v2.31 when not using *--update-drift* the RTC is not read).
Having *hwclock* calculate the drift factor is a good starting point, but for optimal results it will likely need to be adjusted by directly editing the _{ADJTIME_PATH}_ file. For most configurations once a machine's optimal drift factor is crafted it should not need to be changed. Therefore, the old behavior to automatically (re)calculate drift was changed and now requires this option to be used. See the discussion below, under *The Adjust Function*.
This option requires reading the Hardware Clock before setting it. If it cannot be read, then this option will cause the set functions to fail. This can happen, for example, if the Hardware Clock is corrupted by a power failure. In that case, the clock must first be set without this option. Despite it not working, the resulting drift correction factor would be invalid anyway.
*-v*, *--verbose*::
- Display more details about what *hwclock* is doing internally.
+Display more details about what *hwclock* is doing internally.
== NOTES
*Steps to calculate cold drift:*
1::
- *Ensure that NTP daemon will not be launched at startup.*
+*Ensure that NTP daemon will not be launched at startup.*
2::
- The _System Clock_ time must be correct at shutdown!
+The _System Clock_ time must be correct at shutdown!
3::
- Shut down the system.
+Shut down the system.
4::
- Let an extended period pass without changing the Hardware Clock.
+Let an extended period pass without changing the Hardware Clock.
5::
- Start the system.
+Start the system.
6::
- Immediately use *hwclock* to set the correct time, adding the *--update-drift* option.
+Immediately use *hwclock* to set the correct time, adding the *--update-drift* option.
Note: if step 6 uses *--systohc*, then the System Clock must be set correctly (step 6a) just before doing so.
To configure a system to use a particular database all of the files located in its directory must be copied to the root of _/usr/share/zoneinfo_. Files are never used directly from the posix or 'right' subdirectories, e.g., TZ='_right/Europe/Dublin_'. This habit was becoming so common that the upstream zoneinfo project restructured the system's file tree by moving the posix and 'right' subdirectories out of the zoneinfo directory and into sibling directories:
-_/usr/share/zoneinfo_ _/usr/share/zoneinfo-posix_ _/usr/share/zoneinfo-leaps_
+_/usr/share/zoneinfo_, _/usr/share/zoneinfo-posix_, _/usr/share/zoneinfo-leaps_
Unfortunately, some Linux distributions are changing it back to the old tree structure in their packages. So the problem of system administrators reaching into the 'right' subdirectory persists. This causes the system timezone to be configured to include leap seconds while the zoneinfo database is still configured to exclude them. Then when an application such as a World Clock needs the South_Pole timezone file; or an email MTA, or *hwclock* needs the UTC timezone file; they fetch it from the root of _/usr/share/zoneinfo_ , because that is what they are supposed to do. Those files exclude leap seconds, but the System Clock now includes them, causing an incorrect time conversion.
One of the following exit values will be returned:
*EXIT_SUCCESS* ('0' on POSIX systems)::
- Successful program execution.
+Successful program execution.
*EXIT_FAILURE* ('1' on POSIX systems)::
- The operation failed or the command syntax was not valid.
+The operation failed or the command syntax was not valid.
== ENVIRONMENT
*TZ*::
- If this variable is set its value takes precedence over the system configured timezone.
+If this variable is set its value takes precedence over the system configured timezone.
*TZDIR*::
- If this variable is set its value takes precedence over the system configured timezone database directory path.
+If this variable is set its value takes precedence over the system configured timezone database directory path.
== FILES
_{ADJTIME_PATH}_::
- The configuration and state file for hwclock.
+The configuration and state file for hwclock.
_/etc/localtime_::
- The system timezone file.
+The system timezone file.
_/usr/share/zoneinfo/_::
- The system timezone database directory.
+The system timezone database directory.
Device files *hwclock* may try for Hardware Clock access: _/dev/rtc0_ _/dev/rtc_ _/dev/misc/rtc_ _/dev/efirtc_ _/dev/misc/efirtc_
Resources can be specified with these options:
*-M*, *--shmem* _size_::
- Create a shared memory segment of _size_ bytes. The _size_ argument may be followed by the multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, etc. (the "iB" is optional, e.g., "K" has the same meaning as "KiB") or the suffixes KB (=1000), MB (=1000*1000), and so on for GB, etc.
+Create a shared memory segment of _size_ bytes. The _size_ argument may be followed by the multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, etc. (the "iB" is optional, e.g., "K" has the same meaning as "KiB") or the suffixes KB (=1000), MB (=1000*1000), and so on for GB, etc.
*-Q*, *--queue*::
- Create a message queue.
+Create a message queue.
*-S*, *--semaphore* _number_::
- Create a semaphore array with _number_ of elements.
+Create a semaphore array with _number_ of elements.
Other options are:
*-p*, *--mode* _mode_::
- Access permissions for the resource. Default is 0644.
+Access permissions for the resource. Default is 0644.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== AUTHORS
:man source: util-linux {release-version}
:page-layout: base
:command: ipcrm
+:asterisk: *
== NAME
== OPTIONS
*-a*, *--all* [*shm*] [*msg*] [*sem*]::
- Remove all resources. When an option argument is provided, the removal is performed only for the specified resource types. +
- {nbsp} +
- _Warning!_ Do not use *-a* if you are unsure how the software using the resources might react to missing objects. Some programs create these resources at startup and may not have any code to deal with an unexpected disappearance.
+Remove all resources. When an option argument is provided, the removal is performed only for the specified resource types.
++
+_Warning!_ Do not use *-a* if you are unsure how the software using the resources might react to missing objects. Some programs create these resources at startup and may not have any code to deal with an unexpected disappearance.
*-M*, *--shmem-key* _shmkey_::
- Remove the shared memory segment created with _shmkey_ after the last detach is performed.
+Remove the shared memory segment created with _shmkey_ after the last detach is performed.
*-m*, *--shmem-id* _shmid_::
- Remove the shared memory segment identified by _shmid_ after the last detach is performed.
+Remove the shared memory segment identified by _shmid_ after the last detach is performed.
*-Q*, *--queue-key* _msgkey_::
- Remove the message queue created with _msgkey_.
+Remove the message queue created with _msgkey_.
*-q*, *--queue-id* _msgid_::
- Remove the message queue identified by _msgid_.
+Remove the message queue identified by _msgid_.
*-S*, *--semaphore-key* _semkey_::
- Remove the semaphore created with _semkey_.
+Remove the semaphore created with _semkey_.
*-s*, *--semaphore-id* _semid_::
- Remove the semaphore identified by _semid_.
+Remove the semaphore identified by _semid_.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== NOTES
-In its first Linux implementation, *ipcrm* used the deprecated syntax shown in the second line of the *SYNOPSIS*. Functionality present in other +++*+++nix implementations of *ipcrm* has since been added, namely the ability to delete resources by key (not just identifier), and to respect the same command-line syntax. For backward compatibility the previous syntax is still supported.
+//TRANSLATORS: Keep {asterisk} untranslated; it expands to "*nix".
+In its first Linux implementation, *ipcrm* used the deprecated syntax shown in the second line of the *SYNOPSIS*. Functionality present in other {asterisk}nix implementations of *ipcrm* has since been added, namely the ability to delete resources by key (not just identifier), and to respect the same command-line syntax. For backward compatibility the previous syntax is still supported.
== SEE ALSO
== OPTIONS
*-i*, *--id* _id_::
- Show full details on just the one resource element identified by _id_. This option needs to be combined with one of the three resource options: *-m*, *-q* or *-s*.
+Show full details on just the one resource element identified by _id_. This option needs to be combined with one of the three resource options: *-m*, *-q* or *-s*.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
=== Resource options
*-m*, *--shmems*::
- Write information about active shared memory segments.
+Write information about active shared memory segments.
*-q*, *--queues*::
- Write information about active message queues.
+Write information about active message queues.
*-s*, *--semaphores*::
- Write information about active semaphore sets.
+Write information about active semaphore sets.
*-a*, *--all*::
- Write information about all three resources (default).
+Write information about all three resources (default).
=== Output formats
Of these options only one takes effect: the last one specified.
*-c*, *--creator*::
- Show creator and owner.
+Show creator and owner.
*-l*, *--limits*::
- Show resource limits.
+Show resource limits.
*-p*, *--pid*::
- Show PIDs of creator and last operator.
+Show PIDs of creator and last operator.
*-t*, *--time*::
- Write time information. The time of the last control operation that changed the access permissions for all facilities, the time of the last *msgsnd*(2) and *msgrcv*(2) operations on message queues, the time of the last *shmat*(2) and *shmdt*(2) operations on shared memory, and the time of the last *semop*(2) operation on semaphores.
+Write time information. The time of the last control operation that changed the access permissions for all facilities, the time of the last *msgsnd*(2) and *msgrcv*(2) operations on message queues, the time of the last *shmat*(2) and *shmdt*(2) operations on shared memory, and the time of the last *semop*(2) operation on semaphores.
*-u*, *--summary*::
- Show status summary.
+Show status summary.
=== Representation
These affect only the *-l* (*--limits*) option.
*-b*, *--bytes*::
- Print sizes in bytes.
+Print sizes in bytes.
*--human*::
- Print sizes in human-readable format.
+Print sizes in human-readable format.
== CONFORMING TO
-The Linux ipcs utility is not fully compatible to the POSIX ipcs utility. The Linux version does not support the POSIX *-a*, *-b* and *-o* options, but does support the *-l* and *-u* options not defined by POSIX. A portable application shall not use the *-a*, *-b*, *-o*, *-l*, and *-u* options.
+The Linux *ipcs* utility is not fully compatible to the POSIX *ipcs* utility. The Linux version does not support the POSIX *-a*, *-b* and *-o* options, but does support the *-l* and *-u* options not defined by POSIX. A portable application shall not use the *-a*, *-b*, *-o*, *-l*, and *-u* options.
== NOTES
== OPTIONS
*-o*, *--output* _list_::
- Specify which output columns to print. Use *--help* to get a list of all supported columns. The default list of columns may be extended if list is specified in the format _+list_.
+Specify which output columns to print. Use *--help* to get a list of all supported columns. The default list of columns may be extended if list is specified in the format _+list_.
*-d*, *--delay* _seconds_::
- Update interrupt output every _seconds_ intervals.
+Update interrupt output every _seconds_ intervals.
*-s*, *--sort* _column_::
- Specify sort criteria by column name. See *--help* output to get column names. The sort criteria may be changes in interactive mode.
+Specify sort criteria by column name. See *--help* output to get column names. The sort criteria may be changes in interactive mode.
*-S*, *--softirq*::
- Show softirqs information.
+Show softirqs information.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== INTERACTIVE MODE KEY COMMANDS
*i*::
- sort by short irq name or number field
+sort by short irq name or number field
*t*::
- sort by total count of interrupts (the default)
+sort by total count of interrupts (the default)
*d*::
- sort by delta count of interrupts
+sort by delta count of interrupts
*n*::
- sort by long descriptive name field
+sort by long descriptive name field
*q Q*::
- stop updates and exit program
+stop updates and exit program
== AUTHORS
-mailto:pizhenwei@bytedance.com[Zhenwei Pi] +
-mailto:kerolasa@iki.fi[Sami Kerola] +
+mailto:pizhenwei@bytedance.com[Zhenwei Pi],
+mailto:kerolasa@iki.fi[Sami Kerola],
mailto:kzak@redhat.com[Karel Zak]
include::../man-common/bugreports.adoc[]
Depending on the kernel release, the following line disciplines are supported:
*TTY*(*0*)::
- The default line discipline, providing transparent operation (raw mode) as well as the habitual terminal line editing capabilities (cooked mode).
+The default line discipline, providing transparent operation (raw mode) as well as the habitual terminal line editing capabilities (cooked mode).
*SLIP*(*1*)::
- Serial Line IP (SLIP) protocol processor for transmitting TCP/IP packets over serial lines.
+Serial Line IP (SLIP) protocol processor for transmitting TCP/IP packets over serial lines.
*MOUSE*(*2*)::
- Device driver for RS232 connected pointing devices (serial mice).
+Device driver for RS232 connected pointing devices (serial mice).
*PPP*(*3*)::
- Point to Point Protocol (PPP) processor for transmitting network packets over serial lines.
+Point to Point Protocol (PPP) processor for transmitting network packets over serial lines.
*STRIP*(*4*); *AX25*(*5*); *X25*(*6*)::
- Line driver for transmitting X.25 packets over asynchronous serial lines.
+Line driver for transmitting X.25 packets over asynchronous serial lines.
*6PACK*(*7*); *R3964*(*9*)::
- Driver for Simatic R3964 module.
+Driver for Simatic R3964 module.
*IRDA*(*11*)::
- Linux IrDa (infrared data transmission) driver - see http://irda.sourceforge.net/
+Linux IrDa (infrared data transmission) driver - see http://irda.sourceforge.net/
*HDLC*(*13*)::
- Synchronous HDLC driver.
+Synchronous HDLC driver.
*SYNC_PPP*(*14*)::
- Synchronous PPP driver.
+Synchronous PPP driver.
*HCI*(*15*)::
- Bluetooth HCI UART driver.
+Bluetooth HCI UART driver.
*GIGASET_M101*(*16*)::
- Driver for Siemens Gigaset M101 serial DECT adapter.
+Driver for Siemens Gigaset M101 serial DECT adapter.
*PPS*(*18*)::
- Driver for serial line Pulse Per Second (PPS) source.
+Driver for serial line Pulse Per Second (PPS) source.
*GSM0710*(*21*)::
- Driver for GSM 07.10 multiplexing protocol modem (CMUX).
+Driver for GSM 07.10 multiplexing protocol modem (CMUX).
== OPTIONS
*-1*, *--onestopbit*::
- Set the number of stop bits of the serial line to one.
+Set the number of stop bits of the serial line to one.
*-2*, *--twostopbits*::
- Set the number of stop bits of the serial line to two.
+Set the number of stop bits of the serial line to two.
*-7*, *--sevenbits*::
- Set the character size of the serial line to 7 bits.
+Set the character size of the serial line to 7 bits.
*-8*, *--eightbits*::
- Set the character size of the serial line to 8 bits.
+Set the character size of the serial line to 8 bits.
*-d*, *--debug*::
- Keep *ldattach* in the foreground so that it can be interrupted or debugged, and to print verbose messages about its progress to standard error output.
+Keep *ldattach* in the foreground so that it can be interrupted or debugged, and to print verbose messages about its progress to standard error output.
*-e*, *--evenparity*::
- Set the parity of the serial line to even.
+Set the parity of the serial line to even.
-*-i*, *--iflag* [*-*]****__value__...::
- Set the specified bits in the c_iflag word of the serial line. The given _value_ may be a number or a symbolic name. If _value_ is prefixed by a minus sign, the specified bits are cleared instead. Several comma-separated values may be given in order to set and clear multiple bits.
+*-i*, *--iflag* [*-*]_value_...::
+Set the specified bits in the c_iflag word of the serial line. The given _value_ may be a number or a symbolic name. If _value_ is prefixed by a minus sign, the specified bits are cleared instead. Several comma-separated values may be given in order to set and clear multiple bits.
*-n*, *--noparity*::
- Set the parity of the serial line to none.
+Set the parity of the serial line to none.
*-o*, *--oddparity*::
- Set the parity of the serial line to odd.
+Set the parity of the serial line to odd.
*-s*, *--speed* _value_::
- Set the speed (the baud rate) of the serial line to the specified _value_.
+Set the speed (the baud rate) of the serial line to the specified _value_.
*-c*, *--intro-command* _string_::
- Define an intro command that is sent through the serial line before the invocation of ldattach. E.g. in conjunction with line discipline GSM0710, the command ´AT+CMUX=0BSOLr´ is commonly suitable to switch the modem into the CMUX mode.
+Define an intro command that is sent through the serial line before the invocation of ldattach. E.g. in conjunction with line discipline GSM0710, the command 'AT+CMUX=0\r' is commonly suitable to switch the modem into the CMUX mode.
*-p*, *--pause* _value_::
- Sleep for _value_ seconds before the invocation of ldattach. Default is one second.
+Sleep for _value_ seconds before the invocation of ldattach. Default is one second.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== AUTHORS
The _size_ and _offset_ arguments may be followed by the multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is optional, e.g., "K" has the same meaning as "KiB") or the suffixes KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
*-a*, *--all*::
- Show the status of all loop devices. Note that not all information is accessible for non-root users. See also *--list*. The old output format (as printed without *--list)* is deprecated.
+Show the status of all loop devices. Note that not all information is accessible for non-root users. See also *--list*. The old output format (as printed without *--list)* is deprecated.
*-d*, *--detach* _loopdev_...::
- Detach the file or device associated with the specified loop device(s). Note that since Linux v3.7 kernel uses "lazy device destruction". The detach operation does not return *EBUSY* error anymore if device is actively used by system, but it is marked by autoclear flag and destroyed later.
+Detach the file or device associated with the specified loop device(s). Note that since Linux v3.7 kernel uses "lazy device destruction". The detach operation does not return *EBUSY* error anymore if device is actively used by system, but it is marked by autoclear flag and destroyed later.
*-D*, *--detach-all*::
- Detach all associated loop devices.
+Detach all associated loop devices.
*-f*, *--find* [_file_]::
- Find the first unused loop device. If a _file_ argument is present, use the found device as loop device. Otherwise, just print its name.
+Find the first unused loop device. If a _file_ argument is present, use the found device as loop device. Otherwise, just print its name.
*--show*::
- Display the name of the assigned loop device if the *-f* option and a _file_ argument are present.
+Display the name of the assigned loop device if the *-f* option and a _file_ argument are present.
*-L*, *--nooverlap*::
- Check for conflicts between loop devices to avoid situation when the same backing file is shared between more loop devices. If the file is already used by another device then re-use the device rather than a new one. The option makes sense only with *--find*.
+Check for conflicts between loop devices to avoid situation when the same backing file is shared between more loop devices. If the file is already used by another device then re-use the device rather than a new one. The option makes sense only with *--find*.
*-j*, *--associated* _file_ [*-o* _offset_]::
- Show the status of all loop devices associated with the given _file_.
+Show the status of all loop devices associated with the given _file_.
*-o*, *--offset* _offset_::
- The data start is moved _offset_ bytes into the specified file or device. The _offset_ may be followed by the multiplicative suffixes; see above.
+The data start is moved _offset_ bytes into the specified file or device. The _offset_ may be followed by the multiplicative suffixes; see above.
*--sizelimit* _size_::
- The data end is set to no more than _size_ bytes after the data start. The _size_ may be followed by the multiplicative suffixes; see above.
+The data end is set to no more than _size_ bytes after the data start. The _size_ may be followed by the multiplicative suffixes; see above.
*-b*, *--sector-size* _size_::
- Set the logical sector size of the loop device in bytes (since Linux 4.14). The option may be used when create a new loop device as well as stand-alone command to modify sector size of the already existing loop device.
+Set the logical sector size of the loop device in bytes (since Linux 4.14). The option may be used when create a new loop device as well as stand-alone command to modify sector size of the already existing loop device.
*-c*, *--set-capacity* _loopdev_::
- Force the loop driver to reread the size of the file associated with the specified loop device.
+Force the loop driver to reread the size of the file associated with the specified loop device.
*-P*, *--partscan*::
- Force the kernel to scan the partition table on a newly created loop device. Note that the partition table parsing depends on sector sizes. The default is sector size is 512 bytes, otherwise you need to use the option *--sector-size* together with *--partscan*.
+Force the kernel to scan the partition table on a newly created loop device. Note that the partition table parsing depends on sector sizes. The default is sector size is 512 bytes, otherwise you need to use the option *--sector-size* together with *--partscan*.
*-r*, *--read-only*::
- Set up a read-only loop device.
+Set up a read-only loop device.
*--direct-io*[**=on**|*off*]::
- Enable or disable direct I/O for the backing file. The optional argument can be either *on* or *off*. If the argument is omitted, it defaults to *off*.
+Enable or disable direct I/O for the backing file. The optional argument can be either *on* or *off*. If the argument is omitted, it defaults to *off*.
*-v*, *--verbose*::
- Verbose mode.
+Verbose mode.
*-l*, *--list*::
- If a loop device or the *-a* option is specified, print the default columns for either the specified loop device or all loop devices; the default is to print info about all devices. See also *--output*, *--noheadings*, *--raw*, and *--json*.
+If a loop device or the *-a* option is specified, print the default columns for either the specified loop device or all loop devices; the default is to print info about all devices. See also *--output*, *--noheadings*, *--raw*, and *--json*.
*-O*, *--output* _column_[,_column_]...::
- Specify the columns that are to be printed for the *--list* output. Use *--help* to get a list of all supported columns.
+Specify the columns that are to be printed for the *--list* output. Use *--help* to get a list of all supported columns.
*--output-all*::
- Output all available columns.
+Output all available columns.
*-n*, *--noheadings*::
- Don't print headings for *--list* output format.
+Don't print headings for *--list* output format.
*--raw*::
- Use the raw *--list* output format.
+Use the raw *--list* output format.
*-J*, *--json*::
- Use JSON format for *--list* output.
+Use JSON format for *--list* output.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== ENCRYPTION
== ENVIRONMENT
LOOPDEV_DEBUG=all::
- enables debug output.
+enables debug output.
== FILES
_/dev/loop[0..N]_::
- loop block devices
+loop block devices
_/dev/loop-control_::
- loop control device
+loop control device
== EXAMPLE
== AUTHORS
-mailto:kzak@redhat.com[Karel Zak], based on the original version from mailto:tytso@athena.mit.edu[Theodore Ts'o.]
+mailto:kzak@redhat.com[Karel Zak], based on the original version from mailto:tytso@athena.mit.edu[Theodore Ts'o].
include::../man-common/bugreports.adoc[]
Note that topology elements (core, socket, etc.) use a sequential unique ID starting from zero, but CPU logical numbers follow the kernel where there is no guarantee of sequential numbering.
*CPU*::
- The logical CPU number of a CPU as used by the Linux kernel.
+The logical CPU number of a CPU as used by the Linux kernel.
*CORE*::
- The logical core number. A core can contain several CPUs.
+The logical core number. A core can contain several CPUs.
*SOCKET*::
- The logical socket number. A socket can contain several cores.
+The logical socket number. A socket can contain several cores.
*CLUSTER*::
- The logical cluster number. A cluster can contain several cores.
+The logical cluster number. A cluster can contain several cores.
*BOOK*::
- The logical book number. A book can contain several sockets.
+The logical book number. A book can contain several sockets.
*DRAWER*::
- The logical drawer number. A drawer can contain several books.
+The logical drawer number. A drawer can contain several books.
*NODE*::
- The logical NUMA node number. A node can contain several drawers.
+The logical NUMA node number. A node can contain several drawers.
*CACHE*::
- Information about how caches are shared between CPUs.
+Information about how caches are shared between CPUs.
*ADDRESS*::
- The physical address of a CPU.
+The physical address of a CPU.
*ONLINE*::
- Indicator that shows whether the Linux instance currently makes use of the CPU.
+Indicator that shows whether the Linux instance currently makes use of the CPU.
*CONFIGURED*::
- Indicator that shows if the hypervisor has allocated the CPU to the virtual hardware on which the Linux instance runs. CPUs that are configured can be set online by the Linux instance. This column contains data only if your hardware system and hypervisor support dynamic CPU resource allocation.
+Indicator that shows if the hypervisor has allocated the CPU to the virtual hardware on which the Linux instance runs. CPUs that are configured can be set online by the Linux instance. This column contains data only if your hardware system and hypervisor support dynamic CPU resource allocation.
*POLARIZATION*::
- This column contains data for Linux instances that run on virtual hardware with a hypervisor that can switch the CPU dispatching mode (polarization). The polarization can be: +
- {nbsp} +
- *horizontal*;;
- The workload is spread across all available CPUs.
- *vertical*;;
- The workload is concentrated on few CPUs. +
- {nbsp} +
- For vertical polarization, the column also shows the degree of concentration, high, medium, or low. This column contains data only if your hardware system and hypervisor support CPU polarization.
+This column contains data for Linux instances that run on virtual hardware with a hypervisor that can switch the CPU dispatching mode (polarization). The polarization can be:
++
+*horizontal*;;
+The workload is spread across all available CPUs.
+*vertical*;;
+The workload is concentrated on few CPUs.
++
+For vertical polarization, the column also shows the degree of concentration, high, medium, or low. This column contains data only if your hardware system and hypervisor support CPU polarization.
*MAXMHZ*::
- Maximum megahertz value for the CPU. Useful when *lscpu* is used as hardware inventory information gathering tool. Notice that the megahertz value is dynamic, and driven by CPU governor depending on current resource need.
+Maximum megahertz value for the CPU. Useful when *lscpu* is used as hardware inventory information gathering tool. Notice that the megahertz value is dynamic, and driven by CPU governor depending on current resource need.
*MINMHZ*::
- Minimum megahertz value for the CPU.
+Minimum megahertz value for the CPU.
== OPTIONS
*-a*, *--all*::
- Include lines for online and offline CPUs in the output (default for *-e*). This option may only be specified together with option *-e* or *-p*.
+Include lines for online and offline CPUs in the output (default for *-e*). This option may only be specified together with option *-e* or *-p*.
*-B*, *--bytes*::
- Print the sizes in bytes rather than in a human-readable format.
+Print the sizes in bytes rather than in a human-readable format.
*-b*, *--online*::
- Limit the output to online CPUs (default for *-p*). This option may only be specified together with option *-e* or *-p*.
+Limit the output to online CPUs (default for *-p*). This option may only be specified together with option *-e* or *-p*.
*-C*, *--caches*[=_list_]::
- Display details about CPU caches. For details about available information see *--help* output. +
- {nbsp} +
- If the _list_ argument is omitted, all columns for which data is available are included in the command output. +
- {nbsp} +
- When specifying the _list_ argument, the string of option, equal sign (=), and _list_ must not contain any blanks or other whitespace. Examples: '*-C=NAME,ONE-SIZE*' or '*--caches=NAME,ONE-SIZE*'. +
- {nbsp} +
- The default list of columns may be extended if list is specified in the format +list (e.g., lscpu -C=+ALLOC-POLICY).
+Display details about CPU caches. For details about available information see *--help* output.
++
+If the _list_ argument is omitted, all columns for which data is available are included in the command output.
++
+When specifying the _list_ argument, the string of option, equal sign (=), and _list_ must not contain any blanks or other whitespace. Examples: '*-C=NAME,ONE-SIZE*' or '*--caches=NAME,ONE-SIZE*'.
++
+The default list of columns may be extended if list is specified in the format +list (e.g., lscpu -C=+ALLOC-POLICY).
*-c*, *--offline*::
- Limit the output to offline CPUs. This option may only be specified together with option *-e* or *-p*.
+Limit the output to offline CPUs. This option may only be specified together with option *-e* or *-p*.
*-e*, *--extended*[=_list_]::
- Display the CPU information in human-readable format. +
- {nbsp} +
- If the _list_ argument is omitted, all columns for which data is available are included in the command output. +
- {nbsp} +
- When specifying the _list_ argument, the string of option, equal sign (=), and _list_ must not contain any blanks or other whitespace. Examples: '*-e=cpu,node*' or '*--extended=cpu,node*'. +
- {nbsp} +
- The default list of columns may be extended if list is specified in the format +list (e.g., lscpu -e=+MHZ).
+Display the CPU information in human-readable format.
++
+If the _list_ argument is omitted, all columns for which data is available are included in the command output.
++
+When specifying the _list_ argument, the string of option, equal sign (=), and _list_ must not contain any blanks or other whitespace. Examples: '*-e=cpu,node*' or '*--extended=cpu,node*'.
++
+The default list of columns may be extended if list is specified in the format +list (e.g., lscpu -e=+MHZ).
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
*-J*, *--json*::
- Use JSON output format for the default summary or extended output (see *--extended*).
+Use JSON output format for the default summary or extended output (see *--extended*).
*-p*, *--parse*[=_list_]::
- Optimize the command output for easy parsing. +
- {nbsp} +
- If the _list_ argument is omitted, the command output is compatible with earlier versions of *lscpu*. In this compatible format, two commas are used to separate CPU cache columns. If no CPU caches are identified the cache column is omitted. If the _list_ argument is used, cache columns are separated with a colon (:). +
- {nbsp} +
- When specifying the _list_ argument, the string of option, equal sign (=), and _list_ must not contain any blanks or other whitespace. Examples: '*-p=cpu,node*' or '*--parse=cpu,node*'. +
- {nbsp} +
- The default list of columns may be extended if list is specified in the format +list (e.g., lscpu -p=+MHZ).
+Optimize the command output for easy parsing.
++
+If the _list_ argument is omitted, the command output is compatible with earlier versions of *lscpu*. In this compatible format, two commas are used to separate CPU cache columns. If no CPU caches are identified the cache column is omitted. If the _list_ argument is used, cache columns are separated with a colon (:).
++
+When specifying the _list_ argument, the string of option, equal sign (=), and _list_ must not contain any blanks or other whitespace. Examples: '*-p=cpu,node*' or '*--parse=cpu,node*'.
++
+The default list of columns may be extended if list is specified in the format +list (e.g., lscpu -p=+MHZ).
*-s*, *--sysroot* _directory_::
- Gather CPU data for a Linux instance other than the instance from which the *lscpu* command is issued. The specified _directory_ is the system root of the Linux instance to be inspected.
+Gather CPU data for a Linux instance other than the instance from which the *lscpu* command is issued. The specified _directory_ is the system root of the Linux instance to be inspected.
*-x*, *--hex*::
- Use hexadecimal masks for CPU sets (for example "ff"). The default is to print the sets in list format (for example 0,1). Note that before version 2.30 the mask has been printed with 0x prefix.
+Use hexadecimal masks for CPU sets (for example "ff"). The default is to print the sets in list format (for example 0,1). Note that before version 2.30 the mask has been printed with 0x prefix.
*-y*, *--physical*::
- Display physical IDs for all columns with topology elements (core, socket, etc.). Other than logical IDs, which are assigned by *lscpu*, physical IDs are platform-specific values that are provided by the kernel. Physical IDs are not necessarily unique and they might not be arranged sequentially. If the kernel could not retrieve a physical ID for an element *lscpu* prints the dash (-) character. +
- {nbsp} +
- The CPU logical numbers are not affected by this option.
+Display physical IDs for all columns with topology elements (core, socket, etc.). Other than logical IDs, which are assigned by *lscpu*, physical IDs are platform-specific values that are provided by the kernel. Physical IDs are not necessarily unique and they might not be arranged sequentially. If the kernel could not retrieve a physical ID for an element *lscpu* prints the dash (-) character.
++
+The CPU logical numbers are not affected by this option.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*--output-all*::
- Output all available columns. This option must be combined with either *--extended*, *--parse* or *--caches*.
+Output all available columns. This option must be combined with either *--extended*, *--parse* or *--caches*.
== BUGS
== AUTHORS
-mailto:qcai@redhat.com[Cai Qian] +
-mailto:kzak@redhat.com[Karel Zak] +
+mailto:qcai@redhat.com[Cai Qian],
+mailto:kzak@redhat.com[Karel Zak],
mailto:heiko.carstens@de.ibm.com[Heiko Carstens]
== SEE ALSO
== OPTIONS
*-i*, *--id* _id_::
- Show full details on just the one resource element identified by _id_. This option needs to be combined with one of the three resource options: *-m*, *-q* or *-s*. It is possible to override the default output format for this option with the *--list*, *--raw*, *--json* or *--export* option.
+Show full details on just the one resource element identified by _id_. This option needs to be combined with one of the three resource options: *-m*, *-q* or *-s*. It is possible to override the default output format for this option with the *--list*, *--raw*, *--json* or *--export* option.
*-g*, *--global*::
- Show system-wide usage and limits of IPC resources. This option may be combined with one of the three resource options: *-m*, *-q* or *-s*. The default is to show information about all resources.
+Show system-wide usage and limits of IPC resources. This option may be combined with one of the three resource options: *-m*, *-q* or *-s*. The default is to show information about all resources.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
=== Resource options
*-m*, *--shmems*::
- Write information about active shared memory segments.
+Write information about active shared memory segments.
*-q*, *--queues*::
- Write information about active message queues.
+Write information about active message queues.
*-s*, *--semaphores*::
- Write information about active semaphore sets.
+Write information about active semaphore sets.
=== Output formatting
*-c*, *--creator*::
- Show creator and owner.
+Show creator and owner.
*-e*, *--export*::
- Produce output in the form of key="value" pairs. All potentially unsafe value characters are hex-escaped (\x<code>). The key (variable name) will be modified to contain only characters allowed for a shell variable identifiers, for example, USE_PCT instead of USE%.
+Produce output in the form of key="value" pairs. All potentially unsafe value characters are hex-escaped (\x<code>). The key (variable name) will be modified to contain only characters allowed for a shell variable identifiers, for example, USE_PCT instead of USE%.
*-J*, *--json*::
- Use the JSON output format.
+Use the JSON output format.
*-l*, *--list*::
- Use the list output format. This is the default, except when *--id* is used.
+Use the list output format. This is the default, except when *--id* is used.
*-n*, *--newline*::
- Display each piece of information on a separate line.
+Display each piece of information on a separate line.
*--noheadings*::
- Do not print a header line.
+Do not print a header line.
*--notruncate*::
- Don't truncate output.
+Don't truncate output.
*-o*, *--output* _list_::
- Specify which output columns to print. Use *--help* to get a list of all supported columns.
+Specify which output columns to print. Use *--help* to get a list of all supported columns.
*-b*, *--bytes*::
- Print size in bytes rather than in human readable format.
+Print size in bytes rather than in human readable format.
*-r*, *--raw*::
- Raw output (no columnation).
+Raw output (no columnation).
*-t*, *--time*::
- Write time information. The time of the last control operation that changed the access permissions for all facilities, the time of the last *msgsnd*(2) and *msgrcv*(2) operations on message queues, the time of the last *shmat*(2) and *shmdt*(2) operations on shared memory, and the time of the last *semop*(2) operation on semaphores.
+Write time information. The time of the last control operation that changed the access permissions for all facilities, the time of the last *msgsnd*(2) and *msgrcv*(2) operations on message queues, the time of the last *shmat*(2) and *shmdt*(2) operations on shared memory, and the time of the last *semop*(2) operation on semaphores.
*--time-format* _type_::
- Display dates in short, full or iso format. The default is short, this time format is designed to be space efficient and human readable.
+Display dates in short, full or iso format. The default is short, this time format is designed to be space efficient and human readable.
*-P*, *--numeric-perms*::
- Print numeric permissions in PERMS column.
+Print numeric permissions in PERMS column.
== EXIT STATUS
0::
- if OK,
+if OK,
1::
- if incorrect arguments specified,
+if incorrect arguments specified,
2::
- if a serious error occurs.
+if a serious error occurs.
== HISTORY
== AUTHORS
-mailto:ooprala@redhat.com[Ondrej Oprala] +
+mailto:ooprala@redhat.com[Ondrej Oprala],
mailto:kzak@redhat.com[Karel Zak]
== SEE ALSO
== OPTIONS
*-n*, *--noheadings*::
- Don't print headings.
+Don't print headings.
*-o*, *--output* _list_::
- Specify which output columns to print. Use *--help* to get a list of all supported columns. The default list of columns may be extended if list is specified in the format _+list_.
+Specify which output columns to print. Use *--help* to get a list of all supported columns. The default list of columns may be extended if list is specified in the format _+list_.
*-s*, *--sort* _column_::
- Specify sort criteria by column name. See *--help* output to get column names.
+Specify sort criteria by column name. See *--help* output to get column names.
*-J*, *--json*::
- Use JSON output format.
+Use JSON output format.
*-P*, *--pairs*::
- Produce output in the form of key="value" pairs. All potentially unsafe characters are hex-escaped (\x<code>).
+Produce output in the form of key="value" pairs. All potentially unsafe characters are hex-escaped (\x<code>).
*-S*, *--softirq*::
- Show softirqs information.
+Show softirqs information.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== AUTHORS
-mailto:pizhenwei@bytedance.com[Zhenwei Pi] +
-mailto:kerolasa@iki.fi[Sami Kerola] +
+mailto:pizhenwei@bytedance.com[Zhenwei Pi],
+mailto:kerolasa@iki.fi[Sami Kerola],
mailto:kzak@redhat.com[Karel Zak]
include::../man-common/bugreports.adoc[]
== OPTIONS
*-a*, *--all*::
- List each individual memory block, instead of combining memory blocks with similar attributes.
+List each individual memory block, instead of combining memory blocks with similar attributes.
*-b*, *--bytes*::
- Print the SIZE column in bytes rather than in a human-readable format.
+Print the SIZE column in bytes rather than in a human-readable format.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
*-J*, *--json*::
- Use JSON output format.
+Use JSON output format.
*-n*, *--noheadings*::
- Do not print a header line.
+Do not print a header line.
*-o*, *--output* _list_::
- Specify which output columns to print. Use *--help* to get a list of all supported columns. The default list of columns may be extended if _list_ is specified in the format **+**__list__ (e.g., *lsmem -o +NODE*).
+Specify which output columns to print. Use *--help* to get a list of all supported columns. The default list of columns may be extended if _list_ is specified in the format **+**__list__ (e.g., *lsmem -o +NODE*).
*--output-all*::
- Output all available columns.
+Output all available columns.
*-P*, *--pairs*::
- Produce output in the form of key="value" pairs. All potentially unsafe value characters are hex-escaped (\x<code>).
+Produce output in the form of key="value" pairs. All potentially unsafe value characters are hex-escaped (\x<code>).
*-r*, *--raw*::
- Produce output in raw format. All potentially unsafe characters are hex-escaped (\x<code>).
+Produce output in raw format. All potentially unsafe characters are hex-escaped (\x<code>).
*-S*, *--split* _list_::
- Specify which columns (attributes) use to split memory blocks to ranges. The supported columns are STATE, REMOVABLE, NODE and ZONES, or "none". The other columns are silently ignored. For more details see DESCRIPTION above.
+Specify which columns (attributes) use to split memory blocks to ranges. The supported columns are STATE, REMOVABLE, NODE and ZONES, or "none". The other columns are silently ignored. For more details see DESCRIPTION above.
*-s*, *--sysroot* _directory_::
- Gather memory data for a Linux instance other than the instance from which the *lsmem* command is issued. The specified _directory_ is the system root of the Linux instance to be inspected.
+Gather memory data for a Linux instance other than the instance from which the *lsmem* command is issued. The specified _directory_ is the system root of the Linux instance to be inspected.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*--summary*[=_when_]::
- This option controls summary lines output. The optional argument _when_ can be *never*, *always* or *only*. If the _when_ argument is omitted, it defaults to *"only"*. The summary output is suppressed for *--raw*, *--pairs* and *--json*.
+This option controls summary lines output. The optional argument _when_ can be *never*, *always* or *only*. If the _when_ argument is omitted, it defaults to *"only"*. The summary output is suppressed for *--raw*, *--pairs* and *--json*.
== AUTHORS
== OPTIONS
*-J*, *--json*::
- Use JSON output format.
+Use JSON output format.
*-l*, *--list*::
- Use list output format.
+Use list output format.
*-n*, *--noheadings*::
- Do not print a header line.
+Do not print a header line.
*-o*, *--output* _list_::
- Specify which output columns to print. Use *--help* to get a list of all supported columns. +
- {nbsp} +
- The default list of columns may be extended if _list_ is specified in the format **+**__list__ (e.g., *lsns -o +PATH*).
+Specify which output columns to print. Use *--help* to get a list of all supported columns.
++
+The default list of columns may be extended if _list_ is specified in the format **+**__list__ (e.g., *lsns -o +PATH*).
*--output-all*::
- Output all available columns.
+Output all available columns.
*-p*, *--task* _PID_::
- Display only the namespaces held by the process with this _PID_.
+Display only the namespaces held by the process with this _PID_.
*-r*, *--raw*::
- Use the raw output format.
+Use the raw output format.
*-t*, *--type* _type_::
- Display the specified _type_ of namespaces only. The supported types are *mnt*, *net*, *ipc*, *user*, *pid*, *uts*, *cgroup* and *time*. This option may be given more than once.
+Display the specified _type_ of namespaces only. The supported types are *mnt*, *net*, *ipc*, *user*, *pid*, *uts*, *cgroup* and *time*. This option may be given more than once.
*-u*, *--notruncate*::
- Do not truncate text in columns.
+Do not truncate text in columns.
*-W*, *--nowrap*::
- Do not use multi-line text in columns.
+Do not use multi-line text in columns.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== AUTHORS
:man source: util-linux {release-version}
:page-layout: base
:command: mount
+:asterisk: *
== NAME
The device names of disk partitions are unstable; hardware reconfiguration, and adding or removing a device can cause changes in names. This is the reason why it's strongly recommended to use filesystem or partition identifiers like UUID or LABEL. Currently supported identifiers (tags):
-____
LABEL=__label__::
- Human readable filesystem identifier. See also *-L*.
+Human readable filesystem identifier. See also *-L*.
+
UUID=__uuid__::
- Filesystem universally unique identifier. The format of the UUID is usually a series of hex digits separated by hyphens. See also *-U*. +
- {nbsp} +
- Note that *mount* uses UUIDs as strings. The UUIDs from the command line or from *fstab*(5) are not converted to internal binary representation. The string representation of the UUID should be based on lower case characters.
+Filesystem universally unique identifier. The format of the UUID is usually a series of hex digits separated by hyphens. See also *-U*.
++
+Note that *mount* uses UUIDs as strings. The UUIDs from the command line or from *fstab*(5) are not converted to internal binary representation. The string representation of the UUID should be based on lower case characters.
+
PARTLABEL=__label__::
- Human readable partition identifier. This identifier is independent on filesystem and does not change by mkfs or mkswap operations It's supported for example for GUID Partition Tables (GPT).
+Human readable partition identifier. This identifier is independent on filesystem and does not change by mkfs or mkswap operations It's supported for example for GUID Partition Tables (GPT).
+
PARTUUID=__uuid__::
- Partition universally unique identifier. This identifier is independent on filesystem and does not change by mkfs or mkswap operations It's supported for example for GUID Partition Tables (GPT).
+Partition universally unique identifier. This identifier is independent on filesystem and does not change by mkfs or mkswap operations It's supported for example for GUID Partition Tables (GPT).
+
ID=__id__::
- Hardware block device ID as generated by udevd. This identifier is usually based on WWN (unique storage identifier) and assigned by the hardware manufacturer. See *ls /dev/disk/by-id* for more details, this directory and running udevd is required. This identifier is not recommended for generic use as the identifier is not strictly defined and it depends on udev, udev rules and hardware.
-____
+Hardware block device ID as generated by udevd. This identifier is usually based on WWN (unique storage identifier) and assigned by the hardware manufacturer. See *ls /dev/disk/by-id* for more details, this directory and running udevd is required. This identifier is not recommended for generic use as the identifier is not strictly defined and it depends on udev, udev rules and hardware.
The command *lsblk --fs* provides an overview of filesystems, LABELs and UUIDs on available block devices. The command *blkid -p <device>* provides details about a filesystem on the specified device.
The recommended setup is to use tags (e.g. *UUID*=_uuid_) rather than _/dev/disk/by-{label,uuid,id,partuuid,partlabel}_ udev symlinks in the _/etc/fstab_ file. Tags are more readable, robust and portable. The *mount*(8) command internally uses udev symlinks, so the use of symlinks in _/etc/fstab_ has no advantage over tags. For more details see *libblkid*(3).
-The _proc_ filesystem is not associated with a special device, and when mounting it, an arbitrary keyword - for example, __proc__ - can be used instead of a device specification. (The customary choice _none_ is less fortunate: the error message `none already mounted' from *mount* can be confusing.)
+The _proc_ filesystem is not associated with a special device, and when mounting it, an arbitrary keyword - for example, __proc__ - can be used instead of a device specification. (The customary choice _none_ is less fortunate: the error message 'none already mounted' from *mount* can be confusing.)
=== The files /etc/fstab, /etc/mtab and /proc/mounts
Since util-linux 2.35, *mount* does not exit when user permissions are inadequate according to libmount's internal security rules. Instead, it drops suid permissions and continues as regular non-root user. This behavior supports use-cases where root permissions are not necessary (e.g., fuse filesystems, user namespaces, etc).
-For more details, see fstab5. Only the user that mounted a filesystem can unmount it again. If any user should be able to unmount it, then use *users* instead of *user* in the _fstab_ line. The *owner* option is similar to the *user* option, with the restriction that the user must be the owner of the special file. This may be useful e.g. for _/dev/fd_ if a login script makes the console user owner of this device. The *group* option is similar, with the restriction that the user must be a member of the group of the special file.
+For more details, see *fstab*(5). Only the user that mounted a filesystem can unmount it again. If any user should be able to unmount it, then use *users* instead of *user* in the _fstab_ line. The *owner* option is similar to the *user* option, with the restriction that the user must be the owner of the special file. This may be useful e.g. for _/dev/fd_ if a login script makes the console user owner of this device. The *group* option is similar, with the restriction that the user must be a member of the group of the special file.
=== Bind mount operation
Command-line options available for the *mount* command are:
*-a*, *--all*::
- Mount all filesystems (of the given types) mentioned in _fstab_ (except for those whose line contains the *noauto* keyword). The filesystems are mounted following their order in _fstab_. The *mount* command compares filesystem source, target (and fs root for bind mount or btrfs) to detect already mounted filesystems. The kernel table with already mounted filesystems is cached during *mount --all*. This means that all duplicated _fstab_ entries will be mounted. +
- {nbsp} +
- The option *--all* is possible to use for remount operation too. In this case all filters (*-t* and *-O*) are applied to the table of already mounted filesystems. +
- {nbsp} +
- Since version 2.35 is possible to use the command line option *-o* to alter mount options from _fstab_ (see also *--options-mode*). +
- {nbsp} +
- Note that it is a bad practice to use *mount -a* for _fstab_ checking. The recommended solution is *findmnt --verify*.
+Mount all filesystems (of the given types) mentioned in _fstab_ (except for those whose line contains the *noauto* keyword). The filesystems are mounted following their order in _fstab_. The *mount* command compares filesystem source, target (and fs root for bind mount or btrfs) to detect already mounted filesystems. The kernel table with already mounted filesystems is cached during *mount --all*. This means that all duplicated _fstab_ entries will be mounted.
++
+The option *--all* is possible to use for remount operation too. In this case all filters (*-t* and *-O*) are applied to the table of already mounted filesystems.
++
+Since version 2.35 is possible to use the command line option *-o* to alter mount options from _fstab_ (see also *--options-mode*).
++
+Note that it is a bad practice to use *mount -a* for _fstab_ checking. The recommended solution is *findmnt --verify*.
*-B*, *--bind*::
- Remount a subtree somewhere else (so that its contents are available in both places). See above, under *Bind mounts*.
+Remount a subtree somewhere else (so that its contents are available in both places). See above, under *Bind mounts*.
*-c*, *--no-canonicalize*::
- Don't canonicalize paths. The *mount* command canonicalizes all paths (from the command line or _fstab_) by default. This option can be used together with the *-f* flag for already canonicalized absolute paths. The option is designed for mount helpers which call *mount -i*. It is strongly recommended to not use this command-line option for normal mount operations. +
- {nbsp} +
- Note that *mount* does not pass this option to the **/sbin/mount.**__type__ helpers.
+Don't canonicalize paths. The *mount* command canonicalizes all paths (from the command line or _fstab_) by default. This option can be used together with the *-f* flag for already canonicalized absolute paths. The option is designed for mount helpers which call *mount -i*. It is strongly recommended to not use this command-line option for normal mount operations.
++
+Note that *mount* does not pass this option to the **/sbin/mount.**__type__ helpers.
*-F*, *--fork*::
- (Used in conjunction with *-a*.) Fork off a new incarnation of *mount* for each device. This will do the mounts on different devices or different NFS servers in parallel. This has the advantage that it is faster; also NFS timeouts proceed in parallel. A disadvantage is that the order of the mount operations is undefined. Thus, you cannot use this option if you want to mount both _/usr_ and _/usr/spool_.
+(Used in conjunction with *-a*.) Fork off a new incarnation of *mount* for each device. This will do the mounts on different devices or different NFS servers in parallel. This has the advantage that it is faster; also NFS timeouts proceed in parallel. A disadvantage is that the order of the mount operations is undefined. Thus, you cannot use this option if you want to mount both _/usr_ and _/usr/spool_.
*-f, --fake*::
- Causes everything to be done except for the actual system call; if it's not obvious, this "fakes" mounting the filesystem. This option is useful in conjunction with the *-v* flag to determine what the *mount* command is trying to do. It can also be used to add entries for devices that were mounted earlier with the *-n* option. The *-f* option checks for an existing record in _/etc/mtab_ and fails when the record already exists (with a regular non-fake mount, this check is done by the kernel).
+Causes everything to be done except for the actual system call; if it's not obvious, this "fakes" mounting the filesystem. This option is useful in conjunction with the *-v* flag to determine what the *mount* command is trying to do. It can also be used to add entries for devices that were mounted earlier with the *-n* option. The *-f* option checks for an existing record in _/etc/mtab_ and fails when the record already exists (with a regular non-fake mount, this check is done by the kernel).
*-i, --internal-only*::
- Don't call the **/sbin/mount.**__filesystem__ helper even if it exists.
+Don't call the **/sbin/mount.**__filesystem__ helper even if it exists.
*-L*, *--label* _label_::
- Mount the partition that has the specified _label_.
+Mount the partition that has the specified _label_.
*-l*, *--show-labels*::
- Add the labels in the mount output. *mount* must have permission to read the disk device (e.g. be set-user-ID root) for this to work. One can set such a label for ext2, ext3 or ext4 using the *e2label*(8) utility, or for XFS using *xfs_admin*(8), or for reiserfs using *reiserfstune*(8).
+Add the labels in the mount output. *mount* must have permission to read the disk device (e.g. be set-user-ID root) for this to work. One can set such a label for ext2, ext3 or ext4 using the *e2label*(8) utility, or for XFS using *xfs_admin*(8), or for reiserfs using *reiserfstune*(8).
*-M*, *--move*::
- Move a subtree to some other place. See above, the subsection *The move operation*.
+Move a subtree to some other place. See above, the subsection *The move operation*.
*-n*, *--no-mtab*::
- Mount without writing in _/etc/mtab_. This is necessary for example when _/etc_ is on a read-only filesystem.
+Mount without writing in _/etc/mtab_. This is necessary for example when _/etc_ is on a read-only filesystem.
*-N*, *--namespace* _ns_::
- Perform the mount operation in the mount namespace specified by _ns_. _ns_ is either PID of process running in that namespace or special file representing that namespace. +
- {nbsp} +
- *mount* switches to the mount namespace when it reads _/etc/fstab_, writes _/etc/mtab: (or writes to _/run/mount_) and calls the *mount*(2) system call, otherwise it runs in the original mount namespace. This means that the target namespace does not have to contain any libraries or other requirements necessary to execute the *mount*(2) call. +
- {nbsp} +
- See *mount_namespaces*(7) for more information.
+Perform the mount operation in the mount namespace specified by _ns_. _ns_ is either PID of process running in that namespace or special file representing that namespace.
++
+*mount* switches to the mount namespace when it reads _/etc/fstab_, writes _/etc/mtab: (or writes to _/run/mount_) and calls the *mount*(2) system call, otherwise it runs in the original mount namespace. This means that the target namespace does not have to contain any libraries or other requirements necessary to execute the *mount*(2) call.
++
+See *mount_namespaces*(7) for more information.
*-O*, *--test-opts* _opts_::
- Limit the set of filesystems to which the *-a* option applies. In this regard it is like the *-t* option except that *-O* is useless without *-a*. For example, the command +
- {nbsp} +
- *mount -a -O no_netdev* +
- {nbsp} +
- mounts all filesystems except those which have the option _netdev_ specified in the options field in the _/etc/fstab_ file. +
- {nbsp} +
- It is different from *-t* in that each option is matched exactly; a leading *no* at the beginning of one option does not negate the rest. +
- {nbsp} +
- The *-t* and *-O* options are cumulative in effect; that is, the command +
- {nbsp} +
- *mount -a -t ext2 -O _netdev* +
- {nbsp} +
- mounts all ext2 filesystems with the _netdev option, not all filesystems that are either ext2 or have the _netdev option specified.
+Limit the set of filesystems to which the *-a* option applies. In this regard it is like the *-t* option except that *-O* is useless without *-a*. For example, the command
++
+*mount -a -O no_netdev*
++
+mounts all filesystems except those which have the option _netdev_ specified in the options field in the _/etc/fstab_ file.
++
+It is different from *-t* in that each option is matched exactly; a leading *no* at the beginning of one option does not negate the rest.
++
+The *-t* and *-O* options are cumulative in effect; that is, the command
++
+*mount -a -t ext2 -O _netdev*
++
+mounts all ext2 filesystems with the _netdev option, not all filesystems that are either ext2 or have the _netdev option specified.
*-o*, *--options* _opts_::
- Use the specified mount options. The _opts_ argument is a comma-separated list. For example: +
- {nbsp} +
- *mount LABEL=mydisk -o noatime,nodev,nosuid* +
- {nbsp} +
- For more details, see the *FILESYSTEM-INDEPENDENT MOUNT OPTIONS* and *FILESYSTEM-SPECIFIC MOUNT OPTIONS* sections.
+Use the specified mount options. The _opts_ argument is a comma-separated list. For example:
++
+*mount LABEL=mydisk -o noatime,nodev,nosuid*
++
+For more details, see the *FILESYSTEM-INDEPENDENT MOUNT OPTIONS* and *FILESYSTEM-SPECIFIC MOUNT OPTIONS* sections.
*--options-mode* _mode_::
- Controls how to combine options from _fstab_/_mtab_ with options from the command line. _mode_ can be one of *ignore*, *append*, *prepend* or *replace*. For example, *append* means that options from _fstab_ are appended to options from the command line. The default value is *prepend* -- it means command line options are evaluated after _fstab_ options. Note that the last option wins if there are conflicting ones.
+Controls how to combine options from _fstab_/_mtab_ with options from the command line. _mode_ can be one of *ignore*, *append*, *prepend* or *replace*. For example, *append* means that options from _fstab_ are appended to options from the command line. The default value is *prepend* -- it means command line options are evaluated after _fstab_ options. Note that the last option wins if there are conflicting ones.
*--options-source* _source_::
- Source of default options. _source_ is a comma-separated list of *fstab*, *mtab* and *disable*. *disable* disables *fstab* and *mtab* and disables *--options-source-force*. The default value is *fstab,mtab*.
+Source of default options. _source_ is a comma-separated list of *fstab*, *mtab* and *disable*. *disable* disables *fstab* and *mtab* and disables *--options-source-force*. The default value is *fstab,mtab*.
*--options-source-force*::
- Use options from _fstab_/_mtab_ even if both _device_ and _dir_ are specified.
+Use options from _fstab_/_mtab_ even if both _device_ and _dir_ are specified.
*-R*, *--rbind*::
- Remount a subtree and all possible submounts somewhere else (so that its contents are available in both places). See above, the subsection *Bind mounts*.
+Remount a subtree and all possible submounts somewhere else (so that its contents are available in both places). See above, the subsection *Bind mounts*.
*-r*, *--read-only*::
- Mount the filesystem read-only. A synonym is *-o ro*. +
- {nbsp} +
- Note that, depending on the filesystem type, state and kernel behavior, the system may still write to the device. For example, ext3 and ext4 will replay the journal if the filesystem is dirty. To prevent this kind of write access, you may want to mount an ext3 or ext4 filesystem with the *ro,noload* mount options or set the block device itself to read-only mode, see the *blockdev*(8) command.
+Mount the filesystem read-only. A synonym is *-o ro*.
++
+Note that, depending on the filesystem type, state and kernel behavior, the system may still write to the device. For example, ext3 and ext4 will replay the journal if the filesystem is dirty. To prevent this kind of write access, you may want to mount an ext3 or ext4 filesystem with the *ro,noload* mount options or set the block device itself to read-only mode, see the *blockdev*(8) command.
*-s*::
- Tolerate sloppy mount options rather than failing. This will ignore mount options not supported by a filesystem type. Not all filesystems support this option. Currently it's supported by the *mount.nfs* mount helper only.
+Tolerate sloppy mount options rather than failing. This will ignore mount options not supported by a filesystem type. Not all filesystems support this option. Currently it's supported by the *mount.nfs* mount helper only.
*--source* _device_::
- If only one argument for the *mount* command is given, then the argument might be interpreted as the target (mountpoint) or source (device). This option allows you to explicitly define that the argument is the mount source.
+If only one argument for the *mount* command is given, then the argument might be interpreted as the target (mountpoint) or source (device). This option allows you to explicitly define that the argument is the mount source.
*--target* _directory_::
- If only one argument for the mount command is given, then the argument might be interpreted as the target (mountpoint) or source (device). This option allows you to explicitly define that the argument is the mount target.
+If only one argument for the mount command is given, then the argument might be interpreted as the target (mountpoint) or source (device). This option allows you to explicitly define that the argument is the mount target.
*--target-prefix* _directory_::
- Prepend the specified directory to all mount targets. This option can be used to follow _fstab_, but mount operations are done in another place, for example: +
- {nbsp} +
- *mount --all --target-prefix /chroot -o X-mount.mkdir* +
- {nbsp} +
- mounts all from system _fstab_ to `/chroot`, all missing mountpoint are created (due to X-mount.mkdir). See also *--fstab* to use an alternative _fstab_.
+Prepend the specified directory to all mount targets. This option can be used to follow _fstab_, but mount operations are done in another place, for example:
++
+*mount --all --target-prefix /chroot -o X-mount.mkdir*
++
+mounts all from system _fstab_ to _/chroot_, all missing mountpoint are created (due to X-mount.mkdir). See also *--fstab* to use an alternative _fstab_.
*-T*, *--fstab* _path_::
- Specifies an alternative _fstab_ file. If _path_ is a directory, then the files in the directory are sorted by *strverscmp*(3); files that start with "." or without an _.fstab_ extension are ignored. The option can be specified more than once. This option is mostly designed for initramfs or chroot scripts where additional configuration is specified beyond standard system configuration. +
- {nbsp} +
- Note that *mount* does not pass the option *--fstab* to the **/sbin/mount.**__type__ helpers, meaning that the alternative _fstab_ files will be invisible for the helpers. This is no problem for normal mounts, but user (non-root) mounts always require _fstab_ to verify the user's rights.
+Specifies an alternative _fstab_ file. If _path_ is a directory, then the files in the directory are sorted by *strverscmp*(3); files that start with "." or without an _.fstab_ extension are ignored. The option can be specified more than once. This option is mostly designed for initramfs or chroot scripts where additional configuration is specified beyond standard system configuration.
++
+Note that *mount* does not pass the option *--fstab* to the **/sbin/mount.**__type__ helpers, meaning that the alternative _fstab_ files will be invisible for the helpers. This is no problem for normal mounts, but user (non-root) mounts always require _fstab_ to verify the user's rights.
*-t*, *--types* _fstype_::
- The argument following the *-t* is used to indicate the filesystem type. The filesystem types which are currently supported depend on the running kernel. See _/proc/filesystems_ and _/lib/modules/$(uname -r)/kernel/fs_ for a complete list of the filesystems. The most common are ext2, ext3, ext4, xfs, btrfs, vfat, sysfs, proc, nfs and cifs. +
- {nbsp} +
- The programs *mount* and *umount*(8) support filesystem subtypes. The subtype is defined by a '.subtype' suffix. For example 'fuse.sshfs'. It's recommended to use subtype notation rather than add any prefix to the mount source (for example 'sshfs#example.com' is deprecated). +
- {nbsp} +
- If no *-t* option is given, or if the *auto* type is specified, *mount* will try to guess the desired type. *mount* uses the *libblkid*(3) library for guessing the filesystem type; if that does not turn up anything that looks familiar, *mount* will try to read the file _/etc/filesystems_, or, if that does not exist, _/proc/filesystems_. All of the filesystem types listed there will be tried, except for those that are labeled "nodev" (e.g. _devpts_, _proc_ and _nfs_). If _/etc/filesystems_ ends in a line with a single +++*+++, mount will read _/proc/filesystems_ afterwards. While trying, all filesystem types will be mounted with the mount option *silent*. +
- {nbsp} +
- The *auto* type may be useful for user-mounted floppies. Creating a file _/etc/filesystems_ can be useful to change the probe order (e.g., to try vfat before msdos or ext3 before ext2) or if you use a kernel module autoloader. +
- {nbsp} +
- More than one type may be specified in a comma-separated list, for the *-t* option as well as in an _/etc/fstab_ entry. The list of filesystem types for the *-t* option can be prefixed with *no* to specify the filesystem types on which no action should be taken. The prefix *no* has no effect when specified in an _/etc/fstab_ entry. +
- {nbsp} +
- The prefix *no* can be meaningful with the *-a* option. For example, the command +
- {nbsp} +
- *mount -a -t nomsdos,smbfs* +
- {nbsp} +
- mounts all filesystems except those of type _msdos_ and _smbfs_. +
- {nbsp} +
- For most types all the *mount* program has to do is issue a simple *mount*(2) system call, and no detailed knowledge of the filesystem type is required. For a few types however (like nfs, nfs4, cifs, smbfs, ncpfs) an ad hoc code is necessary. The nfs, nfs4, cifs, smbfs, and ncpfs filesystems have a separate mount program. In order to make it possible to treat all types in a uniform way, *mount* will execute the program **/sbin/mount.**__type__ (if that exists) when called with type _type_. Since different versions of the *smbmount* program have different calling conventions, */sbin/mount.smbfs* may have to be a shell script that sets up the desired call.
+The argument following the *-t* is used to indicate the filesystem type. The filesystem types which are currently supported depend on the running kernel. See _/proc/filesystems_ and _/lib/modules/$(uname -r)/kernel/fs_ for a complete list of the filesystems. The most common are ext2, ext3, ext4, xfs, btrfs, vfat, sysfs, proc, nfs and cifs.
++
+The programs *mount* and *umount*(8) support filesystem subtypes. The subtype is defined by a '.subtype' suffix. For example 'fuse.sshfs'. It's recommended to use subtype notation rather than add any prefix to the mount source (for example 'sshfs#example.com' is deprecated).
++
+If no *-t* option is given, or if the *auto* type is specified, *mount* will try to guess the desired type. *mount* uses the *libblkid*(3) library for guessing the filesystem type; if that does not turn up anything that looks familiar, *mount* will try to read the file _/etc/filesystems_, or, if that does not exist, _/proc/filesystems_. All of the filesystem types listed there will be tried, except for those that are labeled "nodev" (e.g. _devpts_, _proc_ and _nfs_). If _/etc/filesystems_ ends in a line with a single {asterisk}, mount will read _/proc/filesystems_ afterwards. While trying, all filesystem types will be mounted with the mount option *silent*.
+//TRANSLATORS: Keep {asterisk} untranslated.
++
+The *auto* type may be useful for user-mounted floppies. Creating a file _/etc/filesystems_ can be useful to change the probe order (e.g., to try vfat before msdos or ext3 before ext2) or if you use a kernel module autoloader.
++
+More than one type may be specified in a comma-separated list, for the *-t* option as well as in an _/etc/fstab_ entry. The list of filesystem types for the *-t* option can be prefixed with *no* to specify the filesystem types on which no action should be taken. The prefix *no* has no effect when specified in an _/etc/fstab_ entry.
++
+The prefix *no* can be meaningful with the *-a* option. For example, the command
++
+*mount -a -t nomsdos,smbfs*
++
+mounts all filesystems except those of type _msdos_ and _smbfs_.
++
+For most types all the *mount* program has to do is issue a simple *mount*(2) system call, and no detailed knowledge of the filesystem type is required. For a few types however (like nfs, nfs4, cifs, smbfs, ncpfs) an ad hoc code is necessary. The nfs, nfs4, cifs, smbfs, and ncpfs filesystems have a separate mount program. In order to make it possible to treat all types in a uniform way, *mount* will execute the program **/sbin/mount.**__type__ (if that exists) when called with type _type_. Since different versions of the *smbmount* program have different calling conventions, */sbin/mount.smbfs* may have to be a shell script that sets up the desired call.
*-U*, *--uuid* _uuid_::
- Mount the partition that has the specified _uuid_.
+Mount the partition that has the specified _uuid_.
*-v*, *--verbose*::
- Verbose mode.
+Verbose mode.
*-w*, *--rw*, *--read-write*::
- Mount the filesystem read/write. Read-write is the kernel default and the *mount* default is to try read-only if the previous mount syscall with read-write flags on write-protected devices of filesystems failed. +
- {nbsp} +
- A synonym is *-o rw*. +
- {nbsp} +
- Note that specifying *-w* on the command line forces *mount* to never try read-only mount on write-protected devices or already mounted read-only filesystems.
+Mount the filesystem read/write. Read-write is the kernel default and the *mount* default is to try read-only if the previous mount syscall with read-write flags on write-protected devices of filesystems failed.
++
+A synonym is *-o rw*.
++
+Note that specifying *-w* on the command line forces *mount* to never try read-only mount on write-protected devices or already mounted read-only filesystems.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== FILESYSTEM-INDEPENDENT MOUNT OPTIONS
Some of these options could be enabled or disabled by default in the system kernel. To check the current setting see the options in _/proc/mounts_. Note that filesystems also have per-filesystem specific default mount options (see for example *tune2fs -l* output for ext_N_ filesystems).
-The following options apply to any filesystem that is being mounted (but not every filesystem actually honors them NDASH e.g., the *sync* option today has an effect only for ext2, ext3, ext4, fat, vfat, ufs and xfs):
+The following options apply to any filesystem that is being mounted (but not every filesystem actually honors them - e.g., the *sync* option today has an effect only for ext2, ext3, ext4, fat, vfat, ufs and xfs):
*async*::
- All I/O to the filesystem should be done asynchronously. (See also the *sync* option.)
+All I/O to the filesystem should be done asynchronously. (See also the *sync* option.)
*atime*::
- Do not use the *noatime* feature, so the inode access time is controlled by kernel defaults. See also the descriptions of the *relatime* and *strictatime* mount options.
+Do not use the *noatime* feature, so the inode access time is controlled by kernel defaults. See also the descriptions of the *relatime* and *strictatime* mount options.
*noatime*::
- Do not update inode access times on this filesystem (e.g. for faster access on the news spool to speed up news servers). This works for all inode types (directories too), so it implies *nodiratime*.
+Do not update inode access times on this filesystem (e.g. for faster access on the news spool to speed up news servers). This works for all inode types (directories too), so it implies *nodiratime*.
*auto*::
- Can be mounted with the *-a* option.
+Can be mounted with the *-a* option.
*noauto*::
- Can only be mounted explicitly (i.e., the *-a* option will not cause the filesystem to be mounted).
+Can only be mounted explicitly (i.e., the *-a* option will not cause the filesystem to be mounted).
**context=**__context__, **fscontext=**__context__, **defcontext=**__context__, and **rootcontext=**__context__::
- The *context=* option is useful when mounting filesystems that do not support extended attributes, such as a floppy or hard disk formatted with VFAT, or systems that are not normally running under SELinux, such as an ext3 or ext4 formatted disk from a non-SELinux workstation. You can also use *context=* on filesystems you do not trust, such as a floppy. It also helps in compatibility with xattr-supporting filesystems on earlier 2.4.<x> kernel versions. Even where xattrs are supported, you can save time not having to label every file by assigning the entire disk one security context. +
- {nbsp} +
- A commonly used option for removable media is *context="system_u:object_r:removable_t*. +
- {nbsp} +
- Two other options are *fscontext=* and *defcontext=*, both of which are mutually exclusive of the *context=* option. This means you can use fscontext and defcontext with each other, but neither can be used with context. +
- {nbsp} +
- The *fscontext=* option works for all filesystems, regardless of their xattr support. The fscontext option sets the overarching filesystem label to a specific security context. This filesystem label is separate from the individual labels on the files. It represents the entire filesystem for certain kinds of permission checks, such as during mount or file creation. Individual file labels are still obtained from the xattrs on the files themselves. The context option actually sets the aggregate context that fscontext provides, in addition to supplying the same label for individual files. +
- {nbsp} +
- You can set the default security context for unlabeled files using *defcontext=* option. This overrides the value set for unlabeled files in the policy and requires a filesystem that supports xattr labeling. +
- {nbsp} +
- The *rootcontext=* option allows you to explicitly label the root inode of a FS being mounted before that FS or inode becomes visible to userspace. This was found to be useful for things like stateless Linux. +
- {nbsp} +
- Note that the kernel rejects any remount request that includes the context option, *even* when unchanged from the current context. +
- {nbsp} +
- *Warning: the* _context_ *value might contain commas*, in which case the value has to be properly quoted, otherwise *mount* will interpret the comma as a separator between mount options. Don't forget that the shell strips off quotes and thus *double quoting is required*. For example: +
- {nbsp} +
- mount -t tmpfs none /mnt -o \ +
- {nbsp} +
- 'context="system_u:object_r:tmp_t:s0:c127,c456",noexec' +
- {nbsp} +
- For more details, see *selinux*(8).
+The *context=* option is useful when mounting filesystems that do not support extended attributes, such as a floppy or hard disk formatted with VFAT, or systems that are not normally running under SELinux, such as an ext3 or ext4 formatted disk from a non-SELinux workstation. You can also use *context=* on filesystems you do not trust, such as a floppy. It also helps in compatibility with xattr-supporting filesystems on earlier 2.4.<x> kernel versions. Even where xattrs are supported, you can save time not having to label every file by assigning the entire disk one security context.
++
+A commonly used option for removable media is *context="system_u:object_r:removable_t*.
++
+Two other options are *fscontext=* and *defcontext=*, both of which are mutually exclusive of the *context=* option. This means you can use fscontext and defcontext with each other, but neither can be used with context.
++
+The *fscontext=* option works for all filesystems, regardless of their xattr support. The fscontext option sets the overarching filesystem label to a specific security context. This filesystem label is separate from the individual labels on the files. It represents the entire filesystem for certain kinds of permission checks, such as during mount or file creation. Individual file labels are still obtained from the xattrs on the files themselves. The context option actually sets the aggregate context that fscontext provides, in addition to supplying the same label for individual files.
++
+You can set the default security context for unlabeled files using *defcontext=* option. This overrides the value set for unlabeled files in the policy and requires a filesystem that supports xattr labeling.
++
+The *rootcontext=* option allows you to explicitly label the root inode of a FS being mounted before that FS or inode becomes visible to userspace. This was found to be useful for things like stateless Linux.
++
+Note that the kernel rejects any remount request that includes the context option, *even* when unchanged from the current context.
++
+*Warning: the* _context_ *value might contain commas*, in which case the value has to be properly quoted, otherwise *mount* will interpret the comma as a separator between mount options. Don't forget that the shell strips off quotes and thus *double quoting is required*. For example:
+____
+mount -t tmpfs none /mnt -o \
+'context="system_u:object_r:tmp_t:s0:c127,c456",noexec'
+____
+
+For more details, see *selinux*(8).
*defaults*::
- Use the default options: *rw*, *suid*, *dev*, *exec*, *auto*, *nouser*, and *async*. +
- {nbsp} +
- Note that the real set of all default mount options depends on the kernel and filesystem type. See the beginning of this section for more details.
+Use the default options: *rw*, *suid*, *dev*, *exec*, *auto*, *nouser*, and *async*.
++
+Note that the real set of all default mount options depends on the kernel and filesystem type. See the beginning of this section for more details.
*dev*::
- Interpret character or block special devices on the filesystem.
+Interpret character or block special devices on the filesystem.
*nodev*::
- Do not interpret character or block special devices on the filesystem.
+Do not interpret character or block special devices on the filesystem.
*diratime*::
- Update directory inode access times on this filesystem. This is the default. (This option is ignored when *noatime* is set.)
+Update directory inode access times on this filesystem. This is the default. (This option is ignored when *noatime* is set.)
*nodiratime*::
- Do not update directory inode access times on this filesystem. (This option is implied when *noatime* is set.)
+Do not update directory inode access times on this filesystem. (This option is implied when *noatime* is set.)
*dirsync*::
- All directory updates within the filesystem should be done synchronously. This affects the following system calls: *creat*(2), *link*(2), *unlink*(2), *symlink*(2), *mkdir*(2), *rmdir*(2), *mknod*(2) and *rename*(2).
+All directory updates within the filesystem should be done synchronously. This affects the following system calls: *creat*(2), *link*(2), *unlink*(2), *symlink*(2), *mkdir*(2), *rmdir*(2), *mknod*(2) and *rename*(2).
*exec*::
- Permit execution of binaries.
+Permit execution of binaries.
*noexec*::
- Do not permit direct execution of any binaries on the mounted filesystem.
+Do not permit direct execution of any binaries on the mounted filesystem.
*group*::
- Allow an ordinary user to mount the filesystem if one of that user's groups matches the group of the device. This option implies the options *nosuid* and *nodev* (unless overridden by subsequent options, as in the option line *group,dev,suid*).
+Allow an ordinary user to mount the filesystem if one of that user's groups matches the group of the device. This option implies the options *nosuid* and *nodev* (unless overridden by subsequent options, as in the option line *group,dev,suid*).
*iversion*::
- Every time the inode is modified, the i_version field will be incremented.
+Every time the inode is modified, the i_version field will be incremented.
*noiversion*::
- Do not increment the i_version inode field.
+Do not increment the i_version inode field.
*mand*::
- Allow mandatory locks on this filesystem. See *fcntl*(2).
+Allow mandatory locks on this filesystem. See *fcntl*(2).
*nomand*::
- Do not allow mandatory locks on this filesystem.
+Do not allow mandatory locks on this filesystem.
*_netdev*::
- The filesystem resides on a device that requires network access (used to prevent the system from attempting to mount these filesystems until the network has been enabled on the system).
+The filesystem resides on a device that requires network access (used to prevent the system from attempting to mount these filesystems until the network has been enabled on the system).
*nofail*::
- Do not report errors for this device if it does not exist.
+Do not report errors for this device if it does not exist.
*relatime*::
- Update inode access times relative to modify or change time. Access time is only updated if the previous access time was earlier than the current modify or change time. (Similar to *noatime*, but it doesn't break *mutt*(1) or other applications that need to know if a file has been read since the last time it was modified.) +
- {nbsp} +
- Since Linux 2.6.30, the kernel defaults to the behavior provided by this option (unless *noatime* was specified), and the *strictatime* option is required to obtain traditional semantics. In addition, since Linux 2.6.30, the file's last access time is always updated if it is more than 1 day old.
+Update inode access times relative to modify or change time. Access time is only updated if the previous access time was earlier than the current modify or change time. (Similar to *noatime*, but it doesn't break *mutt*(1) or other applications that need to know if a file has been read since the last time it was modified.)
++
+Since Linux 2.6.30, the kernel defaults to the behavior provided by this option (unless *noatime* was specified), and the *strictatime* option is required to obtain traditional semantics. In addition, since Linux 2.6.30, the file's last access time is always updated if it is more than 1 day old.
*norelatime*::
- Do not use the *relatime* feature. See also the *strictatime* mount option.
+Do not use the *relatime* feature. See also the *strictatime* mount option.
*strictatime*::
- Allows to explicitly request full atime updates. This makes it possible for the kernel to default to *relatime* or *noatime* but still allow userspace to override it. For more details about the default system mount options see _/proc/mounts_.
+Allows to explicitly request full atime updates. This makes it possible for the kernel to default to *relatime* or *noatime* but still allow userspace to override it. For more details about the default system mount options see _/proc/mounts_.
*nostrictatime*::
- Use the kernel's default behavior for inode access time updates.
+Use the kernel's default behavior for inode access time updates.
*lazytime*::
- Only update times (atime, mtime, ctime) on the in-memory version of the file inode. +
- {nbsp} +
- This mount option significantly reduces writes to the inode table for workloads that perform frequent random writes to preallocated files. +
- {nbsp} +
- The on-disk timestamps are updated only when: +
- {nbsp} +
- * the inode needs to be updated for some change unrelated to file timestamps
- * the application employs *fsync*(2), *syncfs*(2), or *sync*(2)
- * an undeleted inode is evicted from memory
- * more than 24 hours have passed since the inode was written to disk.
+Only update times (atime, mtime, ctime) on the in-memory version of the file inode.
++
+This mount option significantly reduces writes to the inode table for workloads that perform frequent random writes to preallocated files.
++
+The on-disk timestamps are updated only when:
++
+* the inode needs to be updated for some change unrelated to file timestamps
+* the application employs *fsync*(2), *syncfs*(2), or *sync*(2)
+* an undeleted inode is evicted from memory
+* more than 24 hours have passed since the inode was written to disk.
*nolazytime*::
- Do not use the lazytime feature.
+Do not use the lazytime feature.
*suid*::
- Honor set-user-ID and set-group-ID bits or file capabilities when executing programs from this filesystem.
+Honor set-user-ID and set-group-ID bits or file capabilities when executing programs from this filesystem.
*nosuid*::
- Do not honor set-user-ID and set-group-ID bits or file capabilities when executing programs from this filesystem.
+Do not honor set-user-ID and set-group-ID bits or file capabilities when executing programs from this filesystem.
*silent*::
- Turn on the silent flag.
+Turn on the silent flag.
*loud*::
- Turn off the silent flag.
+Turn off the silent flag.
*owner*::
- Allow an ordinary user to mount the filesystem if that user is the owner of the device. This option implies the options *nosuid* and *nodev* (unless overridden by subsequent options, as in the option line *owner,dev,suid*).
+Allow an ordinary user to mount the filesystem if that user is the owner of the device. This option implies the options *nosuid* and *nodev* (unless overridden by subsequent options, as in the option line *owner,dev,suid*).
*remount*::
- Attempt to remount an already-mounted filesystem. This is commonly used to change the mount flags for a filesystem, especially to make a readonly filesystem writable. It does not change device or mount point. +
- {nbsp} +
- The remount operation together with the *bind* flag has special semantics. See above, the subsection *Bind mounts*. +
- {nbsp} +
- The remount functionality follows the standard way the *mount* command works with options from _fstab_. This means that *mount* does not read _fstab_ (or _mtab_) only when both _device_ and _dir_ are specified. +
- {nbsp} +
- *mount -o remount,rw /dev/foo /dir* +
- {nbsp} +
- After this call all old mount options are replaced and arbitrary stuff from _fstab_ (or _mtab_) is ignored, except the loop= option which is internally generated and maintained by the mount command. +
- {nbsp} +
- *mount -o remount,rw /dir* +
- {nbsp} +
- After this call, mount reads _fstab_ and merges these options with the options from the command line (*-o*). If no mountpoint is found in _fstab_, then a remount with unspecified source is allowed. +
- {nbsp} +
- *mount* allows the use of *--all* to remount all already mounted filesystems which match a specified filter (*-O* and *-t*). For example: +
- {nbsp} +
- *mount --all -o remount,ro -t vfat* +
- {nbsp} +
- remounts all already mounted vfat filesystems in read-only mode. Each of the filesystems is remounted by *mount -o remount,ro /dir* semantic. This means the *mount* command reads _fstab_ or _mtab_ and merges these options with the options from the command line.
+Attempt to remount an already-mounted filesystem. This is commonly used to change the mount flags for a filesystem, especially to make a readonly filesystem writable. It does not change device or mount point.
++
+The remount operation together with the *bind* flag has special semantics. See above, the subsection *Bind mounts*.
++
+The remount functionality follows the standard way the *mount* command works with options from _fstab_. This means that *mount* does not read _fstab_ (or _mtab_) only when both _device_ and _dir_ are specified.
++
+*mount -o remount,rw /dev/foo /dir*
++
+After this call all old mount options are replaced and arbitrary stuff from _fstab_ (or _mtab_) is ignored, except the loop= option which is internally generated and maintained by the mount command.
++
+*mount -o remount,rw /dir*
++
+After this call, mount reads _fstab_ and merges these options with the options from the command line (*-o*). If no mountpoint is found in _fstab_, then a remount with unspecified source is allowed.
++
+*mount* allows the use of *--all* to remount all already mounted filesystems which match a specified filter (*-O* and *-t*). For example:
++
+*mount --all -o remount,ro -t vfat*
++
+remounts all already mounted vfat filesystems in read-only mode. Each of the filesystems is remounted by *mount -o remount,ro /dir* semantic. This means the *mount* command reads _fstab_ or _mtab_ and merges these options with the options from the command line.
*ro*::
- Mount the filesystem read-only.
+Mount the filesystem read-only.
*rw*::
- Mount the filesystem read-write.
+Mount the filesystem read-write.
*sync*::
- All I/O to the filesystem should be done synchronously. In the case of media with a limited number of write cycles (e.g. some flash drives), *sync* may cause life-cycle shortening.
+All I/O to the filesystem should be done synchronously. In the case of media with a limited number of write cycles (e.g. some flash drives), *sync* may cause life-cycle shortening.
*user*::
- Allow an ordinary user to mount the filesystem. The name of the mounting user is written to the _mtab_ file (or to the private libmount file in _/run/mount_ on systems without a regular _mtab_) so that this same user can unmount the filesystem again. This option implies the options *noexec*, *nosuid*, and *nodev* (unless overridden by subsequent options, as in the option line *user,exec,dev,suid*).
+Allow an ordinary user to mount the filesystem. The name of the mounting user is written to the _mtab_ file (or to the private libmount file in _/run/mount_ on systems without a regular _mtab_) so that this same user can unmount the filesystem again. This option implies the options *noexec*, *nosuid*, and *nodev* (unless overridden by subsequent options, as in the option line *user,exec,dev,suid*).
*nouser*::
- Forbid an ordinary user to mount the filesystem. This is the default; it does not imply any other options.
+Forbid an ordinary user to mount the filesystem. This is the default; it does not imply any other options.
*users*::
- Allow any user to mount and to unmount the filesystem, even when some other ordinary user mounted it. This option implies the options *noexec*, *nosuid*, and *nodev* (unless overridden by subsequent options, as in the option line *users,exec,dev,suid*).
+Allow any user to mount and to unmount the filesystem, even when some other ordinary user mounted it. This option implies the options *noexec*, *nosuid*, and *nodev* (unless overridden by subsequent options, as in the option line *users,exec,dev,suid*).
*X-**::
- All options prefixed with "X-" are interpreted as comments or as userspace application-specific options. These options are not stored in user space (e.g., _mtab_ file), nor sent to the mount._type_ helpers nor to the *mount*(2) system call. The suggested format is **X-**__appname__._option_.
+All options prefixed with "X-" are interpreted as comments or as userspace application-specific options. These options are not stored in user space (e.g., _mtab_ file), nor sent to the mount._type_ helpers nor to the *mount*(2) system call. The suggested format is **X-**__appname__._option_.
*x-**::
- The same as *X-** options, but stored permanently in user space. This means the options are also available for *umount*(8) or other operations. Note that maintaining mount options in user space is tricky, because it's necessary use libmount-based tools and there is no guarantee that the options will be always available (for example after a move mount operation or in unshared namespace). +
- {nbsp} +
- Note that before util-linux v2.30 the x-* options have not been maintained by libmount and stored in user space (functionality was the same as for X-* now), but due to the growing number of use-cases (in initrd, systemd etc.) the functionality has been extended to keep existing _fstab_ configurations usable without a change.
+The same as *X-** options, but stored permanently in user space. This means the options are also available for *umount*(8) or other operations. Note that maintaining mount options in user space is tricky, because it's necessary use libmount-based tools and there is no guarantee that the options will be always available (for example after a move mount operation or in unshared namespace).
++
+Note that before util-linux v2.30 the x-* options have not been maintained by libmount and stored in user space (functionality was the same as for X-* now), but due to the growing number of use-cases (in initrd, systemd etc.) the functionality has been extended to keep existing _fstab_ configurations usable without a change.
*X-mount.mkdir*[=_mode_]::
- Allow to make a target directory (mountpoint) if it does not exit yet. The optional argument _mode_ specifies the filesystem access mode used for *mkdir*(2) in octal notation. The default mode is 0755. This functionality is supported only for root users or when mount executed without suid permissions. The option is also supported as x-mount.mkdir, this notation is deprecated since v2.30.
+Allow to make a target directory (mountpoint) if it does not exit yet. The optional argument _mode_ specifies the filesystem access mode used for *mkdir*(2) in octal notation. The default mode is 0755. This functionality is supported only for root users or when mount executed without suid permissions. The option is also supported as x-mount.mkdir, this notation is deprecated since v2.30.
*nosymfollow*::
- Do not follow symlinks when resolving paths. Symlinks can still be created, and *readlink*(1), *readlink*(2), *realpath*(1), and *realpath*(3) all still work properly.
+Do not follow symlinks when resolving paths. Symlinks can still be created, and *readlink*(1), *readlink*(2), *realpath*(1), and *realpath*(3) all still work properly.
== FILESYSTEM-SPECIFIC MOUNT OPTIONS
=== Mount options for adfs
**uid=**__value__ and **gid=**__value__::
- Set the owner and group of the files in the filesystem (default: uid=gid=0).
+Set the owner and group of the files in the filesystem (default: uid=gid=0).
**ownmask=**__value__ and **othmask=**__value__::
- Set the permission mask for ADFS 'owner' permissions and 'other' permissions, respectively (default: 0700 and 0077, respectively). See also _/usr/src/linux/Documentation/filesystems/adfs.rst_.
+Set the permission mask for ADFS 'owner' permissions and 'other' permissions, respectively (default: 0700 and 0077, respectively). See also _/usr/src/linux/Documentation/filesystems/adfs.rst_.
=== Mount options for affs
**uid=**__value__ and **gid=**__value__::
- Set the owner and group of the root of the filesystem (default: uid=gid=0, but with option *uid* or *gid* without specified value, the UID and GID of the current process are taken).
+Set the owner and group of the root of the filesystem (default: uid=gid=0, but with option *uid* or *gid* without specified value, the UID and GID of the current process are taken).
**setuid=**__value__ and **setgid=**__value__::
- Set the owner and group of all files.
+Set the owner and group of all files.
**mode=**__value__::
- Set the mode of all files to _value_ & 0777 disregarding the original permissions. Add search permission to directories that have read permission. The value is given in octal.
+Set the mode of all files to _value_ & 0777 disregarding the original permissions. Add search permission to directories that have read permission. The value is given in octal.
*protect*::
- Do not allow any changes to the protection bits on the filesystem.
+Do not allow any changes to the protection bits on the filesystem.
*usemp*::
- Set UID and GID of the root of the filesystem to the UID and GID of the mount point upon the first sync or umount, and then clear this option. Strange...
+Set UID and GID of the root of the filesystem to the UID and GID of the mount point upon the first sync or umount, and then clear this option. Strange...
*verbose*::
- Print an informational message for each successful mount.
+Print an informational message for each successful mount.
**prefix=**__string__::
- Prefix used before volume name, when following a link.
+Prefix used before volume name, when following a link.
**volume=**__string__::
- Prefix (of length at most 30) used before '/' when following a symbolic link.
+Prefix (of length at most 30) used before '/' when following a symbolic link.
**reserved=**__value__::
- (Default: 2.) Number of unused blocks at the start of the device.
+(Default: 2.) Number of unused blocks at the start of the device.
**root=**__value__::
- Give explicitly the location of the root block.
+Give explicitly the location of the root block.
**bs=**__value__::
- Give blocksize. Allowed values are 512, 1024, 2048, 4096.
+Give blocksize. Allowed values are 512, 1024, 2048, 4096.
**grpquota**|**noquota**|**quota**|*usrquota*::
- These options are accepted but ignored. (However, quota utilities may react to such strings in _/etc/fstab_.)
+These options are accepted but ignored. (However, quota utilities may react to such strings in _/etc/fstab_.)
=== Mount options for debugfs
The debugfs filesystem is a pseudo filesystem, traditionally mounted on _/sys/kernel/debug_. As of kernel version 3.4, debugfs has the following options:
**uid=**__n__**, gid=**__n__::
- Set the owner and group of the mountpoint.
+Set the owner and group of the mountpoint.
**mode=**__value__::
- Sets the mode of the mountpoint.
+Sets the mode of the mountpoint.
=== Mount options for devpts
The devpts filesystem is a pseudo filesystem, traditionally mounted on _/dev/pts_. In order to acquire a pseudo terminal, a process opens _/dev/ptmx_; the number of the pseudo terminal is then made available to the process and the pseudo terminal slave can be accessed as _/dev/pts/_<number>.
**uid=**__value__ and **gid=**__value__::
- This sets the owner or the group of newly created pseudo terminals to the specified values. When nothing is specified, they will be set to the UID and GID of the creating process. For example, if there is a tty group with GID 5, then *gid=5* will cause newly created pseudo terminals to belong to the tty group.
+This sets the owner or the group of newly created pseudo terminals to the specified values. When nothing is specified, they will be set to the UID and GID of the creating process. For example, if there is a tty group with GID 5, then *gid=5* will cause newly created pseudo terminals to belong to the tty group.
**mode=**__value__::
- Set the mode of newly created pseudo terminals to the specified value. The default is 0600. A value of *mode=620* and *gid=5* makes "mesg y" the default on newly created pseudo terminals.
+Set the mode of newly created pseudo terminals to the specified value. The default is 0600. A value of *mode=620* and *gid=5* makes "mesg y" the default on newly created pseudo terminals.
*newinstance*::
- Create a private instance of the devpts filesystem, such that indices of pseudo terminals allocated in this new instance are independent of indices created in other instances of devpts. +
- {nbsp} +
- All mounts of devpts without this *newinstance* option share the same set of pseudo terminal indices (i.e., legacy mode). Each mount of devpts with the *newinstance* option has a private set of pseudo terminal indices. +
- {nbsp} +
- This option is mainly used to support containers in the Linux kernel. It is implemented in Linux kernel versions starting with 2.6.29. Further, this mount option is valid only if *CONFIG_DEVPTS_MULTIPLE_INSTANCES* is enabled in the kernel configuration. +
- {nbsp} +
- To use this option effectively, _/dev/ptmx_ must be a symbolic link to _pts/ptmx_. See _Documentation/filesystems/devpts.txt_ in the Linux kernel source tree for details.
+Create a private instance of the devpts filesystem, such that indices of pseudo terminals allocated in this new instance are independent of indices created in other instances of devpts.
++
+All mounts of devpts without this *newinstance* option share the same set of pseudo terminal indices (i.e., legacy mode). Each mount of devpts with the *newinstance* option has a private set of pseudo terminal indices.
++
+This option is mainly used to support containers in the Linux kernel. It is implemented in Linux kernel versions starting with 2.6.29. Further, this mount option is valid only if *CONFIG_DEVPTS_MULTIPLE_INSTANCES* is enabled in the kernel configuration.
++
+To use this option effectively, _/dev/ptmx_ must be a symbolic link to _pts/ptmx_. See _Documentation/filesystems/devpts.txt_ in the Linux kernel source tree for details.
**ptmxmode=**__value__::
- Set the mode for the new _ptmx_ device node in the devpts filesystem. +
- {nbsp} +
- With the support for multiple instances of devpts (see *newinstance* option above), each instance has a private _ptmx_ node in the root of the devpts filesystem (typically _/dev/pts/ptmx_). +
- {nbsp} +
- For compatibility with older versions of the kernel, the default mode of the new _ptmx_ node is 0000. **ptmxmode=**__value__ specifies a more useful mode for the _ptmx_ node and is highly recommended when the *newinstance* option is specified. +
- {nbsp} +
- This option is only implemented in Linux kernel versions starting with 2.6.29. Further, this option is valid only if *CONFIG_DEVPTS_MULTIPLE_INSTANCES* is enabled in the kernel configuration.
+Set the mode for the new _ptmx_ device node in the devpts filesystem.
++
+With the support for multiple instances of devpts (see *newinstance* option above), each instance has a private _ptmx_ node in the root of the devpts filesystem (typically _/dev/pts/ptmx_).
++
+For compatibility with older versions of the kernel, the default mode of the new _ptmx_ node is 0000. **ptmxmode=**__value__ specifies a more useful mode for the _ptmx_ node and is highly recommended when the *newinstance* option is specified.
++
+This option is only implemented in Linux kernel versions starting with 2.6.29. Further, this option is valid only if *CONFIG_DEVPTS_MULTIPLE_INSTANCES* is enabled in the kernel configuration.
=== Mount options for fat
(Note: _fat_ is not a separate filesystem, but a common part of the _msdos_, _umsdos_ and _vfat_ filesystems.)
*blocksize=*{**512**|**1024**|*2048*}::
- Set blocksize (default 512). This option is obsolete.
+Set blocksize (default 512). This option is obsolete.
**uid=**__value__ and **gid=**__value__::
- Set the owner and group of all files. (Default: the UID and GID of the current process.)
+Set the owner and group of all files. (Default: the UID and GID of the current process.)
**umask=**__value__::
- Set the umask (the bitmask of the permissions that are *not* present). The default is the umask of the current process. The value is given in octal.
+Set the umask (the bitmask of the permissions that are *not* present). The default is the umask of the current process. The value is given in octal.
**dmask=**__value__::
- Set the umask applied to directories only. The default is the umask of the current process. The value is given in octal.
+Set the umask applied to directories only. The default is the umask of the current process. The value is given in octal.
**fmask=**__value__::
- Set the umask applied to regular files only. The default is the umask of the current process. The value is given in octal.
+Set the umask applied to regular files only. The default is the umask of the current process. The value is given in octal.
**allow_utime=**__value__::
- This option controls the permission check of mtime/atime. +
- {nbsp} +
- * *20*
- If current process is in group of file's group ID, you can change timestamp.
- * *2*
- Other users can change timestamp.
+This option controls the permission check of mtime/atime.
++
+* *20*
+If current process is in group of file's group ID, you can change timestamp.
+* *2*
+Other users can change timestamp.
-The default is set from `dmask' option. (If the directory is writable, *utime*(2) is also allowed. I.e. ~dmask & 022)
+The default is set from 'dmask' option. (If the directory is writable, *utime*(2) is also allowed. I.e. ~dmask & 022)
Normally *utime*(2) checks that the current process is owner of the file, or that it has the *CAP_FOWNER* capability. But FAT filesystems don't have UID/GID on disk, so the normal check is too inflexible. With this option you can relax it.
**check=**__value__::
- Three different levels of pickiness can be chosen: +
- {nbsp} +
- * *r*[*elaxed*]
- Upper and lower case are accepted and equivalent, long name parts are truncated (e.g. _verylongname.foobar_ becomes _verylong.foo_), leading and embedded spaces are accepted in each name part (name and extension).
- * *n*[*ormal*]
- Like "relaxed", but many special characters (*, ?, <, spaces, etc.) are rejected. This is the default.
- * *s*[*trict*]
- Like "normal", but names that contain long parts or special characters that are sometimes used on Linux but are not accepted by MS-DOS (+, =, etc.) are rejected.
+Three different levels of pickiness can be chosen:
++
+* *r*[*elaxed*]
+Upper and lower case are accepted and equivalent, long name parts are truncated (e.g. _verylongname.foobar_ becomes _verylong.foo_), leading and embedded spaces are accepted in each name part (name and extension).
+* *n*[*ormal*]
+Like "relaxed", but many special characters (*, ?, <, spaces, etc.) are rejected. This is the default.
+* *s*[*trict*]
+Like "normal", but names that contain long parts or special characters that are sometimes used on Linux but are not accepted by MS-DOS (+, =, etc.) are rejected.
**codepage=**__value__::
- Sets the codepage for converting to shortname characters on FAT and VFAT filesystems. By default, codepage 437 is used.
+Sets the codepage for converting to shortname characters on FAT and VFAT filesystems. By default, codepage 437 is used.
**conv=**__mode__::
- This option is obsolete and may fail or be ignored.
+This option is obsolete and may fail or be ignored.
**cvf_format=**__module__::
- Forces the driver to use the CVF (Compressed Volume File) module cvf__module_ instead of auto-detection. If the kernel supports kmod, the cvf_format=xxx option also controls on-demand CVF module loading. This option is obsolete.
+Forces the driver to use the CVF (Compressed Volume File) module cvf__module_ instead of auto-detection. If the kernel supports kmod, the cvf_format=xxx option also controls on-demand CVF module loading. This option is obsolete.
**cvf_option=**__option__::
- Option passed to the CVF module. This option is obsolete.
+Option passed to the CVF module. This option is obsolete.
*debug*::
- Turn on the _debug_ flag. A version string and a list of filesystem parameters will be printed (these data are also printed if the parameters appear to be inconsistent).
+Turn on the _debug_ flag. A version string and a list of filesystem parameters will be printed (these data are also printed if the parameters appear to be inconsistent).
*discard*::
- If set, causes discard/TRIM commands to be issued to the block device when blocks are freed. This is useful for SSD devices and sparse/thinly-provisioned LUNs.
+If set, causes discard/TRIM commands to be issued to the block device when blocks are freed. This is useful for SSD devices and sparse/thinly-provisioned LUNs.
*dos1xfloppy*::
- If set, use a fallback default BIOS Parameter Block configuration, determined by backing device size. These static parameters match defaults assumed by DOS 1.x for 160 kiB, 180 kiB, 320 kiB, and 360 kiB floppies and floppy images.
+If set, use a fallback default BIOS Parameter Block configuration, determined by backing device size. These static parameters match defaults assumed by DOS 1.x for 160 kiB, 180 kiB, 320 kiB, and 360 kiB floppies and floppy images.
*errors=*{**panic**|**continue**|*remount-ro*}::
- Specify FAT behavior on critical errors: panic, continue without doing anything, or remount the partition in read-only mode (default behavior).
+Specify FAT behavior on critical errors: panic, continue without doing anything, or remount the partition in read-only mode (default behavior).
*fat=*{**12**|**16**|*32*}::
- Specify a 12, 16 or 32 bit fat. This overrides the automatic FAT type detection routine. Use with caution!
+Specify a 12, 16 or 32 bit fat. This overrides the automatic FAT type detection routine. Use with caution!
**iocharset=**__value__::
- Character set to use for converting between 8 bit characters and 16 bit Unicode characters. The default is iso8859-1. Long filenames are stored on disk in Unicode format.
+Character set to use for converting between 8 bit characters and 16 bit Unicode characters. The default is iso8859-1. Long filenames are stored on disk in Unicode format.
*nfs=*{**stale_rw**|*nostale_ro*}::
- Enable this only if you want to export the FAT filesystem over NFS. +
- {nbsp} +
- *stale_rw*: This option maintains an index (cache) of directory inodes which is used by the nfs-related code to improve look-ups. Full file operations (read/write) over NFS are supported but with cache eviction at NFS server, this could result in spurious *ESTALE* errors. +
- {nbsp} +
- *nostale_ro*: This option bases the inode number and file handle on the on-disk location of a file in the FAT directory entry. This ensures that *ESTALE* will not be returned after a file is evicted from the inode cache. However, it means that operations such as rename, create and unlink could cause file handles that previously pointed at one file to point at a different file, potentially causing data corruption. For this reason, this option also mounts the filesystem readonly +
- {nbsp} +
- To maintain backward compatibility, *-o nfs* is also accepted, defaulting to *stale_rw*.
+Enable this only if you want to export the FAT filesystem over NFS.
++
+*stale_rw*: This option maintains an index (cache) of directory inodes which is used by the nfs-related code to improve look-ups. Full file operations (read/write) over NFS are supported but with cache eviction at NFS server, this could result in spurious *ESTALE* errors.
++
+*nostale_ro*: This option bases the inode number and file handle on the on-disk location of a file in the FAT directory entry. This ensures that *ESTALE* will not be returned after a file is evicted from the inode cache. However, it means that operations such as rename, create and unlink could cause file handles that previously pointed at one file to point at a different file, potentially causing data corruption. For this reason, this option also mounts the filesystem readonly.
++
+To maintain backward compatibility, *-o nfs* is also accepted, defaulting to *stale_rw*.
*tz=UTC*::
- This option disables the conversion of timestamps between local time (as used by Windows on FAT) and UTC (which Linux uses internally). This is particularly useful when mounting devices (like digital cameras) that are set to UTC in order to avoid the pitfalls of local time.
+This option disables the conversion of timestamps between local time (as used by Windows on FAT) and UTC (which Linux uses internally). This is particularly useful when mounting devices (like digital cameras) that are set to UTC in order to avoid the pitfalls of local time.
**time_offset=**__minutes__::
- Set offset for conversion of timestamps from local time used by FAT to UTC. I.e., _minutes_ will be subtracted from each timestamp to convert it to UTC used internally by Linux. This is useful when the time zone set in the kernel via *settimeofday*(2) is not the time zone used by the filesystem. Note that this option still does not provide correct time stamps in all cases in presence of DST - time stamps in a different DST setting will be off by one hour.
+Set offset for conversion of timestamps from local time used by FAT to UTC. I.e., _minutes_ will be subtracted from each timestamp to convert it to UTC used internally by Linux. This is useful when the time zone set in the kernel via *settimeofday*(2) is not the time zone used by the filesystem. Note that this option still does not provide correct time stamps in all cases in presence of DST - time stamps in a different DST setting will be off by one hour.
*quiet*::
- Turn on the _quiet_ flag. Attempts to chown or chmod files do not return errors, although they fail. Use with caution!
+Turn on the _quiet_ flag. Attempts to chown or chmod files do not return errors, although they fail. Use with caution!
*rodir*::
- FAT has the *ATTR_RO* (read-only) attribute. On Windows, the *ATTR_RO* of the directory will just be ignored, and is used only by applications as a flag (e.g. it's set for the customized folder). +
- {nbsp} +
- If you want to use *ATTR_RO* as read-only flag even for the directory, set this option.
+FAT has the *ATTR_RO* (read-only) attribute. On Windows, the *ATTR_RO* of the directory will just be ignored, and is used only by applications as a flag (e.g. it's set for the customized folder).
++
+If you want to use *ATTR_RO* as read-only flag even for the directory, set this option.
*showexec*::
- If set, the execute permission bits of the file will be allowed only if the extension part of the name is .EXE, .COM, or .BAT. Not set by default.
+If set, the execute permission bits of the file will be allowed only if the extension part of the name is .EXE, .COM, or .BAT. Not set by default.
*sys_immutable*::
- If set, *ATTR_SYS* attribute on FAT is handled as *IMMUTABLE* flag on Linux. Not set by default.
+If set, *ATTR_SYS* attribute on FAT is handled as *IMMUTABLE* flag on Linux. Not set by default.
*flush*::
- If set, the filesystem will try to flush to disk more early than normal. Not set by default.
+If set, the filesystem will try to flush to disk more early than normal. Not set by default.
*usefree*::
- Use the "free clusters" value stored on *FSINFO*. It'll be used to determine number of free clusters without scanning disk. But it's not used by default, because recent Windows don't update it correctly in some case. If you are sure the "free clusters" on *FSINFO* is correct, by this option you can avoid scanning disk.
+Use the "free clusters" value stored on *FSINFO*. It'll be used to determine number of free clusters without scanning disk. But it's not used by default, because recent Windows don't update it correctly in some case. If you are sure the "free clusters" on *FSINFO* is correct, by this option you can avoid scanning disk.
*dots*, *nodots*, *dotsOK=*[**yes**|*no*]::
- Various misguided attempts to force Unix or DOS conventions onto a FAT filesystem.
+Various misguided attempts to force Unix or DOS conventions onto a FAT filesystem.
=== Mount options for hfs
**creator=**__cccc__**, type=**__cccc__::
- Set the creator/type values as shown by the MacOS finder used for creating new files. Default values: '????'.
+Set the creator/type values as shown by the MacOS finder used for creating new files. Default values: '????'.
**uid=**__n__**, gid=**__n__::
- Set the owner and group of all files. (Default: the UID and GID of the current process.)
+Set the owner and group of all files. (Default: the UID and GID of the current process.)
**dir_umask=**__n__**, file_umask=**__n__**, umask=**__n__::
- Set the umask used for all directories, all regular files, or all files and directories. Defaults to the umask of the current process.
+Set the umask used for all directories, all regular files, or all files and directories. Defaults to the umask of the current process.
**session=**__n__::
- Select the CDROM session to mount. Defaults to leaving that decision to the CDROM driver. This option will fail with anything but a CDROM as underlying device.
+Select the CDROM session to mount. Defaults to leaving that decision to the CDROM driver. This option will fail with anything but a CDROM as underlying device.
**part=**__n__::
- Select partition number n from the device. Only makes sense for CDROMs. Defaults to not parsing the partition table at all.
+Select partition number n from the device. Only makes sense for CDROMs. Defaults to not parsing the partition table at all.
*quiet*::
- Don't complain about invalid mount options.
+Don't complain about invalid mount options.
=== Mount options for hpfs
**uid=**__value__ and **gid=**__value__::
- Set the owner and group of all files. (Default: the UID and GID of the current process.)
+Set the owner and group of all files. (Default: the UID and GID of the current process.)
**umask=**__value__::
- Set the umask (the bitmask of the permissions that are *not* present). The default is the umask of the current process. The value is given in octal.
+Set the umask (the bitmask of the permissions that are *not* present). The default is the umask of the current process. The value is given in octal.
*case=*{**lower**|*asis*}::
- Convert all files names to lower case, or leave them. (Default: *case=lower*.)
+Convert all files names to lower case, or leave them. (Default: *case=lower*.)
**conv=**__mode__::
- This option is obsolete and may fail or being ignored.
+This option is obsolete and may fail or being ignored.
*nocheck*::
- Do not abort mounting when certain consistency checks fail.
+Do not abort mounting when certain consistency checks fail.
=== Mount options for iso9660
Rock Ridge is an extension to iso9660 that provides all of these UNIX-like features. Basically there are extensions to each directory record that supply all of the additional information, and when Rock Ridge is in use, the filesystem is indistinguishable from a normal UNIX filesystem (except that it is read-only, of course).
*norock*::
- Disable the use of Rock Ridge extensions, even if available. Cf. *map*.
+Disable the use of Rock Ridge extensions, even if available. Cf. *map*.
*nojoliet*::
- Disable the use of Microsoft Joliet extensions, even if available. Cf. *map*.
+Disable the use of Microsoft Joliet extensions, even if available. Cf. *map*.
*check=*{*r*[*elaxed*]|*s*[*trict*]}::
- With *check=relaxed*, a filename is first converted to lower case before doing the lookup. This is probably only meaningful together with *norock* and *map=normal*. (Default: *check=strict*.)
+With *check=relaxed*, a filename is first converted to lower case before doing the lookup. This is probably only meaningful together with *norock* and *map=normal*. (Default: *check=strict*.)
**uid=**__value__ and **gid=**__value__::
- Give all files in the filesystem the indicated user or group id, possibly overriding the information found in the Rock Ridge extensions. (Default: *uid=0,gid=0*.)
+Give all files in the filesystem the indicated user or group id, possibly overriding the information found in the Rock Ridge extensions. (Default: *uid=0,gid=0*.)
*map=*{*n*[*ormal*]|*o*[*ff*]|*a*[*corn*]}::
- For non-Rock Ridge volumes, normal name translation maps upper to lower case ASCII, drops a trailing `;1', and converts `;' to `.'. With *map=off* no name translation is done. See *norock*. (Default: *map=normal*.) *map=acorn* is like *map=normal* but also apply Acorn extensions if present.
+For non-Rock Ridge volumes, normal name translation maps upper to lower case ASCII, drops a trailing ';1', and converts ';' to '.'. With *map=off* no name translation is done. See *norock*. (Default: *map=normal*.) *map=acorn* is like *map=normal* but also apply Acorn extensions if present.
**mode=**__value__::
- For non-Rock Ridge volumes, give all files the indicated mode. (Default: read and execute permission for everybody.) Octal mode values require a leading 0.
+For non-Rock Ridge volumes, give all files the indicated mode. (Default: read and execute permission for everybody.) Octal mode values require a leading 0.
*unhide*::
- Also show hidden and associated files. (If the ordinary files and the associated or hidden files have the same filenames, this may make the ordinary files inaccessible.)
+Also show hidden and associated files. (If the ordinary files and the associated or hidden files have the same filenames, this may make the ordinary files inaccessible.)
*block=*{**512**|**1024**|*2048*}::
- Set the block size to the indicated value. (Default: *block=1024*.)
+Set the block size to the indicated value. (Default: *block=1024*.)
**conv=**__mode__::
- This option is obsolete and may fail or being ignored.
+This option is obsolete and may fail or being ignored.
*cruft*::
- If the high byte of the file length contains other garbage, set this mount option to ignore the high order bits of the file length. This implies that a file cannot be larger than 16 MB.
+If the high byte of the file length contains other garbage, set this mount option to ignore the high order bits of the file length. This implies that a file cannot be larger than 16 MB.
**session=**__x__::
- Select number of session on a multisession CD.
+Select number of session on a multisession CD.
**sbsector=**__xxx__::
- Session begins from sector xxx.
+Session begins from sector xxx.
The following options are the same as for vfat and specifying them only makes sense when using discs encoded using Microsoft's Joliet extensions.
**iocharset=**__value__::
- Character set to use for converting 16 bit Unicode characters on CD to 8 bit characters. The default is iso8859-1.
+Character set to use for converting 16 bit Unicode characters on CD to 8 bit characters. The default is iso8859-1.
*utf8*::
- Convert 16 bit Unicode characters on CD to UTF-8.
+Convert 16 bit Unicode characters on CD to UTF-8.
=== Mount options for jfs
**iocharset=**__name__::
- Character set to use for converting from Unicode to ASCII. The default is to do no conversion. Use *iocharset=utf8* for UTF8 translations. This requires *CONFIG_NLS_UTF8* to be set in the kernel _.config_ file.
+Character set to use for converting from Unicode to ASCII. The default is to do no conversion. Use *iocharset=utf8* for UTF8 translations. This requires *CONFIG_NLS_UTF8* to be set in the kernel _.config_ file.
**resize=**__value__::
- Resize the volume to _value_ blocks. JFS only supports growing a volume, not shrinking it. This option is only valid during a remount, when the volume is mounted read-write. The *resize* keyword with no value will grow the volume to the full size of the partition.
+Resize the volume to _value_ blocks. JFS only supports growing a volume, not shrinking it. This option is only valid during a remount, when the volume is mounted read-write. The *resize* keyword with no value will grow the volume to the full size of the partition.
*nointegrity*::
- Do not write to the journal. The primary use of this option is to allow for higher performance when restoring a volume from backup media. The integrity of the volume is not guaranteed if the system abnormally ends.
+Do not write to the journal. The primary use of this option is to allow for higher performance when restoring a volume from backup media. The integrity of the volume is not guaranteed if the system abnormally ends.
*integrity*::
- Default. Commit metadata changes to the journal. Use this option to remount a volume where the *nointegrity* option was previously specified in order to restore normal behavior.
+Default. Commit metadata changes to the journal. Use this option to remount a volume where the *nointegrity* option was previously specified in order to restore normal behavior.
*errors=*{**continue**|**remount-ro**|*panic*}::
- Define the behavior when an error is encountered. (Either ignore errors and just mark the filesystem erroneous and continue, or remount the filesystem read-only, or panic and halt the system.)
+Define the behavior when an error is encountered. (Either ignore errors and just mark the filesystem erroneous and continue, or remount the filesystem read-only, or panic and halt the system.)
**noquota**|**quota**|**usrquota**|*grpquota*::
- These options are accepted but ignored.
+These options are accepted but ignored.
=== Mount options for msdos
=== Mount options for ntfs
**iocharset=**__name__::
- Character set to use when returning file names. Unlike VFAT, NTFS suppresses names that contain nonconvertible characters. Deprecated.
+Character set to use when returning file names. Unlike VFAT, NTFS suppresses names that contain nonconvertible characters. Deprecated.
**nls=**__name__::
- New name for the option earlier called _iocharset_.
+New name for the option earlier called _iocharset_.
*utf8*::
- Use UTF-8 for converting file names.
+Use UTF-8 for converting file names.
*uni_xlate=*{**0**|**1**|*2*}::
- For 0 (or `no' or `false'), do not use escape sequences for unknown Unicode characters. For 1 (or `yes' or `true') or 2, use vfat-style 4-byte escape sequences starting with ":". Here 2 gives a little-endian encoding and 1 a byteswapped bigendian encoding.
+For 0 (or 'no' or 'false'), do not use escape sequences for unknown Unicode characters. For 1 (or 'yes' or 'true') or 2, use vfat-style 4-byte escape sequences starting with ":". Here 2 gives a little-endian encoding and 1 a byteswapped bigendian encoding.
*posix=[0|1]*::
- If enabled (posix=1), the filesystem distinguishes between upper and lower case. The 8.3 alias names are presented as hard links instead of being suppressed. This option is obsolete.
+If enabled (posix=1), the filesystem distinguishes between upper and lower case. The 8.3 alias names are presented as hard links instead of being suppressed. This option is obsolete.
**uid=**__value__, **gid=**__value__ and **umask=**__value__::
- Set the file permission on the filesystem. The umask value is given in octal. By default, the files are owned by root and not readable by somebody else.
+Set the file permission on the filesystem. The umask value is given in octal. By default, the files are owned by root and not readable by somebody else.
=== Mount options for overlay
____
**lowerdir=**__directory__::
- Any filesystem, does not need to be on a writable filesystem.
+Any filesystem, does not need to be on a writable filesystem.
**upperdir=**__directory__::
- The upperdir is normally on a writable filesystem.
+The upperdir is normally on a writable filesystem.
**workdir=**__directory__::
- The workdir needs to be an empty directory on the same filesystem as upperdir.
+The workdir needs to be an empty directory on the same filesystem as upperdir.
=== Mount options for reiserfs
Reiserfs is a journaling filesystem.
*conv*::
- Instructs version 3.6 reiserfs software to mount a version 3.5 filesystem, using the 3.6 format for newly created objects. This filesystem will no longer be compatible with reiserfs 3.5 tools.
+Instructs version 3.6 reiserfs software to mount a version 3.5 filesystem, using the 3.6 format for newly created objects. This filesystem will no longer be compatible with reiserfs 3.5 tools.
*hash=*{**rupasov**|**tea**|**r5**|*detect*}::
- Choose which hash function reiserfs will use to find files within directories. +
- {nbsp} +
- * *rupasov*
- A hash invented by Yury Yu. Rupasov. It is fast and preserves locality, mapping lexicographically close file names to close hash values. This option should not be used, as it causes a high probability of hash collisions.
- * *tea*
- A Davis-Meyer function implemented by Jeremy Fitzhardinge. It uses hash permuting bits in the name. It gets high randomness and, therefore, low probability of hash collisions at some CPU cost. This may be used if *EHASHCOLLISION* errors are experienced with the r5 hash.
- * *r5*
- A modified version of the rupasov hash. It is used by default and is the best choice unless the filesystem has huge directories and unusual file-name patterns.
- * *detect*
- Instructs *mount* to detect which hash function is in use by examining the filesystem being mounted, and to write this information into the reiserfs superblock. This is only useful on the first mount of an old format filesystem.
+Choose which hash function reiserfs will use to find files within directories.
++
+*rupasov*;;
+A hash invented by Yury Yu. Rupasov. It is fast and preserves locality, mapping lexicographically close file names to close hash values. This option should not be used, as it causes a high probability of hash collisions.
+
+*tea*;;
+A Davis-Meyer function implemented by Jeremy Fitzhardinge. It uses hash permuting bits in the name. It gets high randomness and, therefore, low probability of hash collisions at some CPU cost. This may be used if *EHASHCOLLISION* errors are experienced with the r5 hash.
+
+*r5*;;
+A modified version of the rupasov hash. It is used by default and is the best choice unless the filesystem has huge directories and unusual file-name patterns.
+
+*detect*;;
+Instructs *mount* to detect which hash function is in use by examining the filesystem being mounted, and to write this information into the reiserfs superblock. This is only useful on the first mount of an old format filesystem.
*hashed_relocation*::
- Tunes the block allocator. This may provide performance improvements in some situations.
+Tunes the block allocator. This may provide performance improvements in some situations.
*no_unhashed_relocation*::
- Tunes the block allocator. This may provide performance improvements in some situations.
+Tunes the block allocator. This may provide performance improvements in some situations.
*noborder*::
- Disable the border allocator algorithm invented by Yury Yu. Rupasov. This may provide performance improvements in some situations.
+Disable the border allocator algorithm invented by Yury Yu. Rupasov. This may provide performance improvements in some situations.
*nolog*::
- Disable journaling. This will provide slight performance improvements in some situations at the cost of losing reiserfs's fast recovery from crashes. Even with this option turned on, reiserfs still performs all journaling operations, save for actual writes into its journaling area. Implementation of _nolog_ is a work in progress.
+Disable journaling. This will provide slight performance improvements in some situations at the cost of losing reiserfs's fast recovery from crashes. Even with this option turned on, reiserfs still performs all journaling operations, save for actual writes into its journaling area. Implementation of _nolog_ is a work in progress.
*notail*::
- By default, reiserfs stores small files and `file tails' directly into its tree. This confuses some utilities such as *lilo*(8). This option is used to disable packing of files into the tree.
+By default, reiserfs stores small files and 'file tails' directly into its tree. This confuses some utilities such as *lilo*(8). This option is used to disable packing of files into the tree.
*replayonly*::
- Replay the transactions which are in the journal, but do not actually mount the filesystem. Mainly used by _reiserfsck_.
+Replay the transactions which are in the journal, but do not actually mount the filesystem. Mainly used by _reiserfsck_.
**resize=**__number__::
- A remount option which permits online expansion of reiserfs partitions. Instructs reiserfs to assume that the device has _number_ blocks. This option is designed for use with devices which are under logical volume management (LVM). There is a special _resizer_ utility which can be obtained from _ftp://ftp.namesys.com/pub/reiserfsprogs_.
+A remount option which permits online expansion of reiserfs partitions. Instructs reiserfs to assume that the device has _number_ blocks. This option is designed for use with devices which are under logical volume management (LVM). There is a special _resizer_ utility which can be obtained from _ftp://ftp.namesys.com/pub/reiserfsprogs_.
*user_xattr*::
- Enable Extended User Attributes. See the *attr*(1) manual page.
+Enable Extended User Attributes. See the *attr*(1) manual page.
*acl*::
- Enable POSIX Access Control Lists. See the *acl*(5) manual page.
+Enable POSIX Access Control Lists. See the *acl*(5) manual page.
*barrier=none* / *barrier=flush*::
- This disables / enables the use of write barriers in the journaling code. *barrier=none* disables, *barrier=flush* enables (default). This also requires an IO stack which can support barriers, and if reiserfs gets an error on a barrier write, it will disable barriers again with a warning. Write barriers enforce proper on-disk ordering of journal commits, making volatile disk write caches safe to use, at some performance penalty. If your disks are battery-backed in one way or another, disabling barriers may safely improve performance.
+This disables / enables the use of write barriers in the journaling code. *barrier=none* disables, *barrier=flush* enables (default). This also requires an IO stack which can support barriers, and if reiserfs gets an error on a barrier write, it will disable barriers again with a warning. Write barriers enforce proper on-disk ordering of journal commits, making volatile disk write caches safe to use, at some performance penalty. If your disks are battery-backed in one way or another, disabling barriers may safely improve performance.
=== Mount options for ubifs
The following mount options are available:
*bulk_read*::
- Enable bulk-read. VFS read-ahead is disabled because it slows down the filesystem. Bulk-Read is an internal optimization. Some flashes may read faster if the data are read at one go, rather than at several read requests. For example, OneNAND can do "read-while-load" if it reads more than one NAND page.
+Enable bulk-read. VFS read-ahead is disabled because it slows down the filesystem. Bulk-Read is an internal optimization. Some flashes may read faster if the data are read at one go, rather than at several read requests. For example, OneNAND can do "read-while-load" if it reads more than one NAND page.
*no_bulk_read*::
- Do not bulk-read. This is the default.
+Do not bulk-read. This is the default.
*chk_data_crc*::
- Check data CRC-32 checksums. This is the default.
+Check data CRC-32 checksums. This is the default.
*no_chk_data_crc*::
- Do not check data CRC-32 checksums. With this option, the filesystem does not check CRC-32 checksum for data, but it does check it for the internal indexing information. This option only affects reading, not writing. CRC-32 is always calculated when writing the data.
+Do not check data CRC-32 checksums. With this option, the filesystem does not check CRC-32 checksum for data, but it does check it for the internal indexing information. This option only affects reading, not writing. CRC-32 is always calculated when writing the data.
*compr=*{**none**|**lzo**|*zlib*}::
- Select the default compressor which is used when new files are written. It is still possible to read compressed files if mounted with the *none* option.
+Select the default compressor which is used when new files are written. It is still possible to read compressed files if mounted with the *none* option.
=== Mount options for udf
UDF is the "Universal Disk Format" filesystem defined by OSTA, the Optical Storage Technology Association, and is often used for DVD-ROM, frequently in the form of a hybrid UDF/ISO-9660 filesystem. It is, however, perfectly usable by itself on disk drives, flash drives and other block devices. See also _iso9660_.
*uid=*::
- Make all files in the filesystem belong to the given user. uid=forget can be specified independently of (or usually in addition to) uid=<user> and results in UDF not storing uids to the media. In fact the recorded uid is the 32-bit overflow uid -1 as defined by the UDF standard. The value is given as either <user> which is a valid user name or the corresponding decimal user id, or the special string "forget".
+Make all files in the filesystem belong to the given user. uid=forget can be specified independently of (or usually in addition to) uid=<user> and results in UDF not storing uids to the media. In fact the recorded uid is the 32-bit overflow uid -1 as defined by the UDF standard. The value is given as either <user> which is a valid user name or the corresponding decimal user id, or the special string "forget".
*gid=*::
- Make all files in the filesystem belong to the given group. gid=forget can be specified independently of (or usually in addition to) gid=<group> and results in UDF not storing gids to the media. In fact the recorded gid is the 32-bit overflow gid -1 as defined by the UDF standard. The value is given as either <group> which is a valid group name or the corresponding decimal group id, or the special string "forget".
+Make all files in the filesystem belong to the given group. gid=forget can be specified independently of (or usually in addition to) gid=<group> and results in UDF not storing gids to the media. In fact the recorded gid is the 32-bit overflow gid -1 as defined by the UDF standard. The value is given as either <group> which is a valid group name or the corresponding decimal group id, or the special string "forget".
*umask=*::
- Mask out the given permissions from all inodes read from the filesystem. The value is given in octal.
+Mask out the given permissions from all inodes read from the filesystem. The value is given in octal.
*mode=*::
- If mode= is set the permissions of all non-directory inodes read from the filesystem will be set to the given mode. The value is given in octal.
+If *mode=* is set the permissions of all non-directory inodes read from the filesystem will be set to the given mode. The value is given in octal.
*dmode=*::
- If dmode= is set the permissions of all directory inodes read from the filesystem will be set to the given dmode. The value is given in octal.
+If *dmode=* is set the permissions of all directory inodes read from the filesystem will be set to the given dmode. The value is given in octal.
*bs=*::
- Set the block size. Default value prior to kernel version 2.6.30 was 2048. Since 2.6.30 and prior to 4.11 it was logical device block size with fallback to 2048. Since 4.11 it is logical block size with fallback to any valid block size between logical device block size and 4096. +
- {nbsp} +
- For other details see the mkudffs8 2.0+ manpage, sections *COMPATIBILITY* and *BLOCK SIZE*.
+Set the block size. Default value prior to kernel version 2.6.30 was 2048. Since 2.6.30 and prior to 4.11 it was logical device block size with fallback to 2048. Since 4.11 it is logical block size with fallback to any valid block size between logical device block size and 4096.
++
+For other details see the *mkudffs*(8) 2.0+ manpage, sections *COMPATIBILITY* and *BLOCK SIZE*.
*unhide*::
- Show otherwise hidden files.
+Show otherwise hidden files.
*undelete*::
- Show deleted files in lists.
+Show deleted files in lists.
*adinicb*::
- Embed data in the inode. (default)
+Embed data in the inode. (default)
*noadinicb*::
- Don't embed data in the inode.
+Don't embed data in the inode.
*shortad*::
- Use short UDF address descriptors.
+Use short UDF address descriptors.
*longad*::
- Use long UDF address descriptors. (default)
+Use long UDF address descriptors. (default)
*nostrict*::
- Unset strict conformance.
+Unset strict conformance.
*iocharset=*::
- Set the NLS character set. This requires kernel compiled with *CONFIG_UDF_NLS* option.
+Set the NLS character set. This requires kernel compiled with *CONFIG_UDF_NLS* option.
*utf8*::
- Set the UTF-8 character set.
+Set the UTF-8 character set.
=== Mount options for debugging and disaster recovery
*novrs*::
- Ignore the Volume Recognition Sequence and attempt to mount anyway.
+Ignore the Volume Recognition Sequence and attempt to mount anyway.
*session=*::
- Select the session number for multi-session recorded optical media. (default= last session)
+Select the session number for multi-session recorded optical media. (default= last session)
*anchor=*::
- Override standard anchor location. (default= 256)
+Override standard anchor location. (default= 256)
*lastblock=*::
- Set the last block of the filesystem.
+Set the last block of the filesystem.
=== Unused historical mount options that may be encountered and should be removed
*uid=ignore*::
- Ignored, use uid=<user> instead.
+Ignored, use uid=<user> instead.
*gid=ignore*::
- Ignored, use gid=<group> instead.
+Ignored, use gid=<group> instead.
*volume=*::
- Unimplemented and ignored.
+Unimplemented and ignored.
*partition=*::
- Unimplemented and ignored.
+Unimplemented and ignored.
*fileset=*::
- Unimplemented and ignored.
+Unimplemented and ignored.
*rootdir=*::
- Unimplemented and ignored.
+Unimplemented and ignored.
=== Mount options for ufs
**ufstype=**__value__::
- UFS is a filesystem widely used in different operating systems. The problem are differences among implementations. Features of some implementations are undocumented, so its hard to recognize the type of ufs automatically. That's why the user must specify the type of ufs by mount option. Possible values are: +
- {nbsp} +
- * *old*
- Old format of ufs, this is the default, read only. (Don't forget to give the *-r* option.)
- * *44bsd*
- For filesystems created by a BSD-like system (NetBSD, FreeBSD, OpenBSD).
- * *ufs2*
- Used in FreeBSD 5.x supported as read-write.
- * *5xbsd*
- Synonym for ufs2.
- * *sun*
- For filesystems created by SunOS or Solaris on Sparc.
- * *sunx86*
- For filesystems created by Solaris on x86.
- * *hp*
- For filesystems created by HP-UX, read-only.
- * *nextstep*
- For filesystems created by NeXTStep (on NeXT station) (currently read only).
- * *nextstep-cd*
- For NextStep CDROMs (block_size == 2048), read-only.
- * *openstep*
- For filesystems created by OpenStep (currently read only). The same filesystem type is also used by Mac OS X.
+UFS is a filesystem widely used in different operating systems. The problem are differences among implementations. Features of some implementations are undocumented, so its hard to recognize the type of ufs automatically. That's why the user must specify the type of ufs by mount option. Possible values are:
++
+*old*;;
+Old format of ufs, this is the default, read only. (Don't forget to give the *-r* option.)
+
+*44bsd*;;
+For filesystems created by a BSD-like system (NetBSD, FreeBSD, OpenBSD).
+
+*ufs2*;;
+Used in FreeBSD 5.x supported as read-write.
+
+*5xbsd*;;
+Synonym for ufs2.
+
+*sun*;;
+For filesystems created by SunOS or Solaris on Sparc.
+
+*sunx86*;;
+For filesystems created by Solaris on x86.
+
+*hp*;;
+For filesystems created by HP-UX, read-only.
+
+*nextstep*;;
+For filesystems created by NeXTStep (on NeXT station) (currently read only).
+
+*nextstep-cd*;;
+For NextStep CDROMs (block_size == 2048), read-only.
+
+*openstep*;;
+For filesystems created by OpenStep (currently read only). The same filesystem type is also used by Mac OS X.
**onerror=**__value__::
- Set behavior on error: +
- {nbsp} +
- * *panic*
- If an error is encountered, cause a kernel panic.
- * [**lock**|**umount**|*repair*]
- These mount options don't do anything at present; when an error is encountered only a console message is printed.
+Set behavior on error:
+
+*panic*;;
+If an error is encountered, cause a kernel panic.
+
+[**lock**|**umount**|*repair*];;
+These mount options don't do anything at present; when an error is encountered only a console message is printed.
=== Mount options for umsdos
First of all, the mount options for _fat_ are recognized. The *dotsOK* option is explicitly killed by _vfat_. Furthermore, there are
*uni_xlate*::
- Translate unhandled Unicode characters to special escaped sequences. This lets you backup and restore filenames that are created with any Unicode characters. Without this option, a '?' is used when no translation is possible. The escape character is ':' because it is otherwise invalid on the vfat filesystem. The escape sequence that gets used, where u is the Unicode character, is: ':', (u & 0x3f), ((u>>6) & 0x3f), (u>>12).
+Translate unhandled Unicode characters to special escaped sequences. This lets you backup and restore filenames that are created with any Unicode characters. Without this option, a '?' is used when no translation is possible. The escape character is ':' because it is otherwise invalid on the vfat filesystem. The escape sequence that gets used, where u is the Unicode character, is: ':', (u & 0x3f), ((u>>6) & 0x3f), (u>>12).
*posix*::
- Allow two files with names that only differ in case. This option is obsolete.
+Allow two files with names that only differ in case. This option is obsolete.
*nonumtail*::
- First try to make a short name without sequence number, before trying _name~num.ext_.
+First try to make a short name without sequence number, before trying _name~num.ext_.
*utf8*::
- UTF8 is the filesystem safe 8-bit encoding of Unicode that is used by the console. It can be enabled for the filesystem with this option or disabled with utf8=0, utf8=no or utf8=false. If _uni_xlate_ gets set, UTF8 gets disabled.
+UTF8 is the filesystem safe 8-bit encoding of Unicode that is used by the console. It can be enabled for the filesystem with this option or disabled with utf8=0, utf8=no or utf8=false. If _uni_xlate_ gets set, UTF8 gets disabled.
**shortname=**__mode__::
- Defines the behavior for creation and display of filenames which fit into 8.3 characters. If a long name for a file exists, it will always be the preferred one for display. There are four __mode__s: +
- {nbsp} +
- * *lower*
- Force the short name to lower case upon display; store a long name when the short name is not all upper case.
- * *win95*
- Force the short name to upper case upon display; store a long name when the short name is not all upper case.
- * *winnt*
- Display the short name as is; store a long name when the short name is not all lower case or all upper case.
- * *mixed*
- Display the short name as is; store a long name when the short name is not all upper case. This mode is the default since Linux 2.6.32.
+Defines the behavior for creation and display of filenames which fit into 8.3 characters. If a long name for a file exists, it will always be the preferred one for display. There are four __mode__s:
+
+*lower*;;
+Force the short name to lower case upon display; store a long name when the short name is not all upper case.
+
+*win95*;;
+Force the short name to upper case upon display; store a long name when the short name is not all upper case.
+
+*winnt*;;
+Display the short name as is; store a long name when the short name is not all lower case or all upper case.
+
+*mixed*;;
+Display the short name as is; store a long name when the short name is not all upper case. This mode is the default since Linux 2.6.32.
=== Mount options for usbfs
**devuid=**__uid__ and **devgid=**__gid__ and **devmode=**__mode__::
- Set the owner and group and mode of the device files in the usbfs filesystem (default: uid=gid=0, mode=0644). The mode is given in octal.
+Set the owner and group and mode of the device files in the usbfs filesystem (default: uid=gid=0, mode=0644). The mode is given in octal.
**busuid=**__uid__ and **busgid=**__gid__ and **busmode=**__mode__::
- Set the owner and group and mode of the bus directories in the usbfs filesystem (default: uid=gid=0, mode=0555). The mode is given in octal.
+Set the owner and group and mode of the bus directories in the usbfs filesystem (default: uid=gid=0, mode=0555). The mode is given in octal.
**listuid=**__uid__ and **listgid=**__gid__ and **listmode=**__mode__::
- Set the owner and group and mode of the file _devices_ (default: uid=gid=0, mode=0444). The mode is given in octal.
+Set the owner and group and mode of the file _devices_ (default: uid=gid=0, mode=0444). The mode is given in octal.
== DM-VERITY SUPPORT (experimental)
The device-mapper verity target provides read-only transparent integrity checking of block devices using kernel crypto API. The *mount* command can open the dm-verity device and do the integrity verification before on the device filesystem is mounted. Requires libcryptsetup with in libmount (optionally via *dlopen*(3)). If libcryptsetup supports extracting the root hash of an already mounted device, existing devices will be automatically reused in case of a match. Mount options for dm-verity:
**verity.hashdevice=**__path__::
- Path to the hash tree device associated with the source volume to pass to dm-verity.
+Path to the hash tree device associated with the source volume to pass to dm-verity.
**verity.roothash=**__hex__::
- Hex-encoded hash of the root of _verity.hashdevice_. Mutually exclusive with _verity.roothashfile._
+Hex-encoded hash of the root of _verity.hashdevice_. Mutually exclusive with _verity.roothashfile._
**verity.roothashfile=**__path__::
- Path to file containing the hex-encoded hash of the root of _verity.hashdevice._ Mutually exclusive with _verity.roothash._
+Path to file containing the hex-encoded hash of the root of _verity.hashdevice._ Mutually exclusive with _verity.roothash._
**verity.hashoffset=**__offset__::
- If the hash tree device is embedded in the source volume, _offset_ (default: 0) is used by dm-verity to get to the tree.
+If the hash tree device is embedded in the source volume, _offset_ (default: 0) is used by dm-verity to get to the tree.
**verity.fecdevice=**__path__::
- Path to the Forward Error Correction (FEC) device associated with the source volume to pass to dm-verity. Optional. Requires kernel built with *CONFIG_DM_VERITY_FEC*.
+Path to the Forward Error Correction (FEC) device associated with the source volume to pass to dm-verity. Optional. Requires kernel built with *CONFIG_DM_VERITY_FEC*.
**verity.fecoffset=**__offset__::
- If the FEC device is embedded in the source volume, _offset_ (default: 0) is used by dm-verity to get to the FEC area. Optional.
+If the FEC device is embedded in the source volume, _offset_ (default: 0) is used by dm-verity to get to the FEC area. Optional.
**verity.fecroots=**__value__::
- Parity bytes for FEC (default: 2). Optional.
+Parity bytes for FEC (default: 2). Optional.
**verity.roothashsig=**__path__::
- Path to pkcs7 signature of root hash hex string. Requires crypt_activate_by_signed_key() from cryptsetup and kernel built with *CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG*. For device reuse, signatures have to be either used by all mounts of a device or by none. Optional.
+Path to *pkcs7*(1ssl) signature of root hash hex string. Requires crypt_activate_by_signed_key() from cryptsetup and kernel built with *CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG*. For device reuse, signatures have to be either used by all mounts of a device or by none. Optional.
Supported since util-linux v2.35.
will set up the loop device _/dev/loop3_ to correspond to the file _/tmp/disk.img_, and then mount this device on _/mnt_.
-If no explicit loop device is mentioned (but just an option `**-o loop**' is given), then *mount* will try to find some unused loop device and use that, for example
+If no explicit loop device is mentioned (but just an option '**-o loop**' is given), then *mount* will try to find some unused loop device and use that, for example
____
*mount /tmp/disk.img /mnt -o loop*
*mount* has the following exit status values (the bits can be ORed):
*0*::
- success
+success
*1*::
- incorrect invocation or permissions
+incorrect invocation or permissions
*2*::
- system error (out of memory, cannot fork, no more loop devices)
+system error (out of memory, cannot fork, no more loop devices)
*4*::
- internal *mount* bug
+internal *mount* bug
*8*::
- user interrupt
+user interrupt
*16*::
- problems writing or locking _/etc/mtab_
+problems writing or locking _/etc/mtab_
*32*::
- mount failure
+mount failure
*64*::
- some mount succeeded +
- {nbsp} +
- The command *mount -a* returns 0 (all succeeded), 32 (all failed), or 64 (some failed, some succeeded).
+some mount succeeded
++
+The command *mount -a* returns 0 (all succeeded), 32 (all failed), or 64 (some failed, some succeeded).
== EXTERNAL HELPERS
== ENVIRONMENT
LIBMOUNT_FSTAB=<path>::
- overrides the default location of the _fstab_ file (ignored for suid)
+overrides the default location of the _fstab_ file (ignored for suid)
LIBMOUNT_MTAB=<path>::
- overrides the default location of the _mtab_ file (ignored for suid)
+overrides the default location of the _mtab_ file (ignored for suid)
LIBMOUNT_DEBUG=all::
- enables libmount debug output
+enables libmount debug output
LIBBLKID_DEBUG=all::
- enables libblkid debug output
+enables libblkid debug output
LOOPDEV_DEBUG=all::
- enables loop device setup debug output
+enables loop device setup debug output
== FILES
See also "*The files /etc/fstab, /etc/mtab and /proc/mounts*" section above.
_/etc/fstab_::
- filesystem table
+filesystem table
_/run/mount_::
- libmount private runtime directory
+libmount private runtime directory
_/etc/mtab_::
- table of mounted filesystems or symlink to _/proc/mounts_
+table of mounted filesystems or symlink to _/proc/mounts_
_/etc/mtab~_::
- lock file (unused on systems with _mtab_ symlink)
+lock file (unused on systems with _mtab_ symlink)
_/etc/mtab.tmp_::
- temporary file (unused on systems with _mtab_ symlink)
+temporary file (unused on systems with _mtab_ symlink)
_/etc/filesystems_::
- a list of filesystem types to try
+a list of filesystem types to try
== HISTORY
Checking files on NFS filesystems referenced by file descriptors (i.e. the *fcntl* and *ioctl* families of functions) may lead to inconsistent results due to the lack of a consistency check in the kernel even if the *noac* mount option is used.
-The *loop* option with the *offset* or *sizelimit* options used may fail when using older kernels if the *mount* command can't confirm that the size of the block device has been configured as requested. This situation can be worked around by using the *losetup* command manually before calling *mount* with the configured loop device.
+The *loop* option with the *offset* or *sizelimit* options used may fail when using older kernels if the *mount* command can't confirm that the size of the block device has been configured as requested. This situation can be worked around by using the *losetup*(8) command manually before calling *mount* with the configured loop device.
== AUTHORS
== OPTIONS
*-d*, *--fs-devno*::
- Show the major/minor numbers of the device that is mounted on the given directory.
+Show the major/minor numbers of the device that is mounted on the given directory.
*-q*, *--quiet*::
- Be quiet - don't print anything.
+Be quiet - don't print anything.
*--nofollow*::
- Do not follow symbolic link if it the last element of the _directory_ path.
+Do not follow symbolic link if it the last element of the _directory_ path.
*-x*, *--devno*::
- Show the major/minor numbers of the given blockdevice on standard output.
+Show the major/minor numbers of the given blockdevice on standard output.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== EXIT STATUS
*mountpoint* has the following exit status values:
*0*::
- success; the directory is a mountpoint, or device is block device on *--devno*
+success; the directory is a mountpoint, or device is block device on *--devno*
*1*::
- failure; incorrect invocation, permissions or system error
+failure; incorrect invocation, permissions or system error
*32*::
- failure; the directory is not a mountpoint, or device is not a block device on *--devno*
+failure; the directory is not a mountpoint, or device is not a block device on *--devno*
== ENVIRONMENT
LIBMOUNT_DEBUG=all::
- enables libmount debug output.
+enables libmount debug output.
== NOTES
Enterable namespaces are:
*mount namespace*::
- Mounting and unmounting filesystems will not affect the rest of the system, except for filesystems which are explicitly marked as shared (with *mount --make-shared*; see _/proc/self/mountinfo_ for the *shared* flag). For further details, see *mount_namespaces*(7) and the discussion of the *CLONE_NEWNS* flag in *clone*(2).
+Mounting and unmounting filesystems will not affect the rest of the system, except for filesystems which are explicitly marked as shared (with *mount --make-shared*; see _/proc/self/mountinfo_ for the *shared* flag). For further details, see *mount_namespaces*(7) and the discussion of the *CLONE_NEWNS* flag in *clone*(2).
*UTS namespace*::
- Setting hostname or domainname will not affect the rest of the system. For further details, see *uts_namespaces*(7).
+Setting hostname or domainname will not affect the rest of the system. For further details, see *uts_namespaces*(7).
*IPC namespace*::
- The process will have an independent namespace for POSIX message queues as well as System V message queues, semaphore sets and shared memory segments. For further details, see *ipc_namespaces*(7).
+The process will have an independent namespace for POSIX message queues as well as System V message queues, semaphore sets and shared memory segments. For further details, see *ipc_namespaces*(7).
*network namespace*::
- The process will have independent IPv4 and IPv6 stacks, IP routing tables, firewall rules, the _/proc/net_ and _/sys/class/net_ directory trees, sockets, etc. For further details, see *network_namespaces*(7).
+The process will have independent IPv4 and IPv6 stacks, IP routing tables, firewall rules, the _/proc/net_ and _/sys/class/net_ directory trees, sockets, etc. For further details, see *network_namespaces*(7).
*PID namespace*::
- Children will have a set of PID to process mappings separate from the *nsenter* process. *nsenter* will fork by default if changing the PID namespace, so that the new program and its children share the same PID namespace and are visible to each other. If *--no-fork* is used, the new program will be exec'ed without forking. For further details, see *pid_namespaces*(7).
+Children will have a set of PID to process mappings separate from the *nsenter* process. *nsenter* will fork by default if changing the PID namespace, so that the new program and its children share the same PID namespace and are visible to each other. If *--no-fork* is used, the new program will be exec'ed without forking. For further details, see *pid_namespaces*(7).
*user namespace*::
- The process will have a distinct set of UIDs, GIDs and capabilities. For further details, see *user_namespaces*(7).
+The process will have a distinct set of UIDs, GIDs and capabilities. For further details, see *user_namespaces*(7).
*cgroup namespace*::
- The process will have a virtualized view of _/proc/self/cgroup_, and new cgroup mounts will be rooted at the namespace cgroup root. For further details, see *cgroup_namespaces*(7).
+The process will have a virtualized view of _/proc/self/cgroup_, and new cgroup mounts will be rooted at the namespace cgroup root. For further details, see *cgroup_namespaces*(7).
*time namespace*::
- The process can have a distinct view of *CLOCK_MONOTONIC* and/or *CLOCK_BOOTTIME* which can be changed using _/proc/self/timens_offsets_. For further details, see *time_namespaces*(7).
+The process can have a distinct view of *CLOCK_MONOTONIC* and/or *CLOCK_BOOTTIME* which can be changed using _/proc/self/timens_offsets_. For further details, see *time_namespaces*(7).
== OPTIONS
-Various of the options below that relate to namespaces take an optional _file_ argument. This should be one of the _/proc/[pid]/ns/+++*+++_ files described in *namespaces*(7), or the pathname of a bind mount that was created on one of those files.
+//TRANSLATORS: Keep {asterisk} untranslated.
+Various of the options below that relate to namespaces take an optional _file_ argument. This should be one of the _/proc/[pid]/ns/{asterisk}_ files described in *namespaces*(7), or the pathname of a bind mount that was created on one of those files.
+//TRANSLATORS: Keep {asterisk} untranslated.
*-a*, *--all*::
- Enter all namespaces of the target process by the default _/proc/[pid]/ns/+++*+++_ namespace paths. The default paths to the target process namespaces may be overwritten by namespace specific options (e.g., *--all --mount*=[_path_]). +
- {nbsp} +
- The user namespace will be ignored if the same as the caller's current user namespace. It prevents a caller that has dropped capabilities from regaining those capabilities via a call to setns(). See *setns*(2) for more details.
+Enter all namespaces of the target process by the default _/proc/[pid]/ns/{asterisk}_ namespace paths. The default paths to the target process namespaces may be overwritten by namespace specific options (e.g., *--all --mount*=[_path_]).
++
+The user namespace will be ignored if the same as the caller's current user namespace. It prevents a caller that has dropped capabilities from regaining those capabilities via a call to setns(). See *setns*(2) for more details.
*-t*, *--target* _PID_::
- Specify a target process to get contexts from. The paths to the contexts specified by _pid_ are: +
- {nbsp} +
-____
- /proc/_pid_/ns/mnt;;
- the mount namespace
- /proc/_pid_/ns/uts;;
- the UTS namespace
- /proc/_pid_/ns/ipc;;
- the IPC namespace
- /proc/_pid_/ns/net;;
- the network namespace
- /proc/_pid_/ns/pid;;
- the PID namespace
- /proc/_pid_/ns/user;;
- the user namespace
- /proc/_pid_/ns/cgroup;;
- the cgroup namespace
- /proc/_pid_/ns/time;;
- the time namespace
- /proc/_pid_/root;;
- the root directory
- /proc/_pid_/cwd;;
- the working directory respectively
-____
+Specify a target process to get contexts from. The paths to the contexts specified by _pid_ are:
+
+/proc/_pid_/ns/mnt;;
+the mount namespace
+/proc/_pid_/ns/uts;;
+the UTS namespace
+/proc/_pid_/ns/ipc;;
+the IPC namespace
+/proc/_pid_/ns/net;;
+the network namespace
+/proc/_pid_/ns/pid;;
+the PID namespace
+/proc/_pid_/ns/user;;
+the user namespace
+/proc/_pid_/ns/cgroup;;
+the cgroup namespace
+/proc/_pid_/ns/time;;
+the time namespace
+/proc/_pid_/root;;
+the root directory
+/proc/_pid_/cwd;;
+the working directory respectively
*-m*, *--mount*[=_file_]::
- Enter the mount namespace. If no file is specified, enter the mount namespace of the target process. If _file_ is specified, enter the mount namespace specified by _file_.
+Enter the mount namespace. If no file is specified, enter the mount namespace of the target process. If _file_ is specified, enter the mount namespace specified by _file_.
*-u*, *--uts*[=_file_]::
- Enter the UTS namespace. If no file is specified, enter the UTS namespace of the target process. If _file_ is specified, enter the UTS namespace specified by _file_.
+Enter the UTS namespace. If no file is specified, enter the UTS namespace of the target process. If _file_ is specified, enter the UTS namespace specified by _file_.
*-i*, *--ipc*[=_file_]::
- Enter the IPC namespace. If no file is specified, enter the IPC namespace of the target process. If _file_ is specified, enter the IPC namespace specified by _file_.
+Enter the IPC namespace. If no file is specified, enter the IPC namespace of the target process. If _file_ is specified, enter the IPC namespace specified by _file_.
*-n*, *--net*[=_file_]::
- Enter the network namespace. If no file is specified, enter the network namespace of the target process. If _file_ is specified, enter the network namespace specified by _file_.
+Enter the network namespace. If no file is specified, enter the network namespace of the target process. If _file_ is specified, enter the network namespace specified by _file_.
*-p*, *--pid*[=_file_]::
- Enter the PID namespace. If no file is specified, enter the PID namespace of the target process. If _file_ is specified, enter the PID namespace specified by _file_.
+Enter the PID namespace. If no file is specified, enter the PID namespace of the target process. If _file_ is specified, enter the PID namespace specified by _file_.
*-U*, *--user*[=_file_]::
- Enter the user namespace. If no file is specified, enter the user namespace of the target process. If _file_ is specified, enter the user namespace specified by _file_. See also the *--setuid* and *--setgid* options.
+Enter the user namespace. If no file is specified, enter the user namespace of the target process. If _file_ is specified, enter the user namespace specified by _file_. See also the *--setuid* and *--setgid* options.
*-C*, *--cgroup*[=_file_]::
- Enter the cgroup namespace. If no file is specified, enter the cgroup namespace of the target process. If _file_ is specified, enter the cgroup namespace specified by _file_.
+Enter the cgroup namespace. If no file is specified, enter the cgroup namespace of the target process. If _file_ is specified, enter the cgroup namespace specified by _file_.
*-T*, *--time*[=_file_]::
- Enter the time namespace. If no file is specified, enter the time namespace of the target process. If _file_ is specified, enter the time namespace specified by _file_.
+Enter the time namespace. If no file is specified, enter the time namespace of the target process. If _file_ is specified, enter the time namespace specified by _file_.
*-G*, *--setgid* _gid_::
- Set the group ID which will be used in the entered namespace and drop supplementary groups. *nsenter* always sets GID for user namespaces, the default is 0.
+Set the group ID which will be used in the entered namespace and drop supplementary groups. *nsenter* always sets GID for user namespaces, the default is 0.
*-S*, *--setuid* _uid_::
- Set the user ID which will be used in the entered namespace. *nsenter* always sets UID for user namespaces, the default is 0.
+Set the user ID which will be used in the entered namespace. *nsenter* always sets UID for user namespaces, the default is 0.
*--preserve-credentials*::
- Don't modify UID and GID when enter user namespace. The default is to drops supplementary groups and sets GID and UID to 0.
+Don't modify UID and GID when enter user namespace. The default is to drops supplementary groups and sets GID and UID to 0.
*-r*, *--root*[=_directory_]::
- Set the root directory. If no directory is specified, set the root directory to the root directory of the target process. If directory is specified, set the root directory to the specified directory.
+Set the root directory. If no directory is specified, set the root directory to the root directory of the target process. If directory is specified, set the root directory to the specified directory.
*-w*, *--wd*[=_directory_]::
- Set the working directory. If no directory is specified, set the working directory to the working directory of the target process. If directory is specified, set the working directory to the specified directory.
+Set the working directory. If no directory is specified, set the working directory to the working directory of the target process. If directory is specified, set the working directory to the specified directory.
*-F*, *--no-fork*::
- Do not fork before exec'ing the specified program. By default, when entering a PID namespace, *nsenter* calls *fork* before calling *exec* so that any children will also be in the newly entered PID namespace.
+Do not fork before exec'ing the specified program. By default, when entering a PID namespace, *nsenter* calls *fork* before calling *exec* so that any children will also be in the newly entered PID namespace.
*-Z*, *--follow-context*::
- Set the SELinux security context used for executing a new process according to already running process specified by *--target* PID. (The util-linux has to be compiled with SELinux support otherwise the option is unavailable.)
+Set the SELinux security context used for executing a new process according to already running process specified by *--target* PID. (The util-linux has to be compiled with SELinux support otherwise the option is unavailable.)
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== AUTHORS
-mailto:biederm@xmission.com[Eric Biederman] +
+mailto:biederm@xmission.com[Eric Biederman],
mailto:kzak@redhat.com[Karel Zak]
== SEE ALSO
== OPTIONS
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== EXAMPLE
:man source: util-linux {release-version}
:page-layout: base
:command: prlimit
+:colon: :
== NAME
Because of the nature of limits, the soft limit must be lower or equal to the high limit (also called the ceiling). To see all available resource limits, refer to the RESOURCE OPTIONS section.
-* _soft_+++:+++_hard_ Specify both limits.
-* _soft_+++:+++ Specify only the soft limit.
-* +++:+++_hard_ Specify only the hard limit.
+//TRANSLATORS: Keep {colon} untranslated.
+* _soft_{colon}_hard_ Specify both limits.
+* _soft_{colon} Specify only the soft limit.
+* {colon}__hard__ Specify only the hard limit.
* _value_ Specify both limits to the same value.
== GENERAL OPTIONS
*-h, --help*::
- Display help text and exit.
+Display help text and exit.
*--noheadings*::
- Do not print a header line.
+Do not print a header line.
*-o, --output* _list_::
- Define the output columns to use. If no output arrangement is specified, then a default set is used. Use *--help* to get a list of all supported columns.
+Define the output columns to use. If no output arrangement is specified, then a default set is used. Use *--help* to get a list of all supported columns.
*-p, --pid*::
- Specify the process id; if none is given, the running process will be used.
+Specify the process id; if none is given, the running process will be used.
*--raw*::
- Use the raw output format.
+Use the raw output format.
*--verbose*::
- Verbose mode.
+Verbose mode.
*-V, --version*::
- Display version information and exit.
+Display version information and exit.
== RESOURCE OPTIONS
*-c, --core*[=_limits_]::
- Maximum size of a core file.
+Maximum size of a core file.
*-d, --data*[=_limits_]::
- Maximum data size.
+Maximum data size.
*-e, --nice*[=_limits_]::
- Maximum nice priority allowed to raise.
+Maximum nice priority allowed to raise.
*-f, --fsize*[=_limits_]::
- Maximum file size.
+Maximum file size.
*-i, --sigpending*[=_limits_]::
- Maximum number of pending signals.
+Maximum number of pending signals.
*-l, --memlock*[=_limits_]::
- Maximum locked-in-memory address space.
+Maximum locked-in-memory address space.
*-m, --rss*[=_limits_]::
- Maximum Resident Set Size (RSS).
+Maximum Resident Set Size (RSS).
*-n, --nofile*[=_limits_]::
- Maximum number of open files.
+Maximum number of open files.
*-q, --msgqueue*[=_limits_]::
- Maximum number of bytes in POSIX message queues.
+Maximum number of bytes in POSIX message queues.
*-r, --rtprio*[=_limits_]::
- Maximum real-time priority.
+Maximum real-time priority.
*-s, --stack*[=_limits_]::
- Maximum size of the stack.
+Maximum size of the stack.
*-t, --cpu*[=_limits_]::
- CPU time, in seconds.
+CPU time, in seconds.
*-u, --nproc*[=_limits_]::
- Maximum number of processes.
+Maximum number of processes.
*-v, --as*[=_limits_]::
- Address space limit.
+Address space limit.
*-x, --locks*[=_limits_]::
- Maximum number of file locks held.
+Maximum number of file locks held.
*-y, --rttime*[=_limits_]::
- Timeout for real-time tasks.
+Timeout for real-time tasks.
== NOTES
== EXAMPLES
*prlimit --pid 13134*::
- Display limit values for all current resources.
+Display limit values for all current resources.
*prlimit --pid 13134 --rss --nofile=1024:4095*::
- Display the limits of the RSS, and set the soft and hard limits for the number of open files to 1024 and 4095, respectively.
+Display the limits of the RSS, and set the soft and hard limits for the number of open files to 1024 and 4095, respectively.
*prlimit --pid 13134 --nproc=512:*::
- Modify only the soft limit for the number of processes.
+Modify only the soft limit for the number of processes.
*prlimit --pid $$ --nproc=unlimited*::
- Set for the current process both the soft and ceiling values for the number of processes to unlimited.
+Set for the current process both the soft and ceiling values for the number of processes to unlimited.
*prlimit --cpu=10 sort -u hugefile*::
- Set both the soft and hard CPU time limit to ten seconds and run 'sort'.
+Set both the soft and hard CPU time limit to ten seconds and run 'sort'.
== AUTHORS
== OPTIONS
*-a*, *--all*::
- Print all symbols in the mapfile. By default the procedures with reported ticks are not printed.
+Print all symbols in the mapfile. By default the procedures with reported ticks are not printed.
*-b*, *--histbin*::
- Print individual histogram-bin counts.
+Print individual histogram-bin counts.
*-i*, *--info*::
- Info. This makes *readprofile* only print the profiling step used by the kernel. The profiling step is the resolution of the profiling buffer, and is chosen during kernel configuration (through *make config*), or in the kernel's command line. If the *-t* (terse) switch is used together with *-i* only the decimal number is printed.
+Info. This makes *readprofile* only print the profiling step used by the kernel. The profiling step is the resolution of the profiling buffer, and is chosen during kernel configuration (through *make config*), or in the kernel's command line. If the *-t* (terse) switch is used together with *-i* only the decimal number is printed.
*-m*, *--mapfile* _mapfile_::
- Specify a mapfile, which by default is _/usr/src/linux/System.map_. You should specify the map file on cmdline if your current kernel isn't the last one you compiled, or if you keep System.map elsewhere. If the name of the map file ends with _.gz_ it is decompressed on the fly.
+Specify a mapfile, which by default is _/usr/src/linux/System.map_. You should specify the map file on cmdline if your current kernel isn't the last one you compiled, or if you keep System.map elsewhere. If the name of the map file ends with _.gz_ it is decompressed on the fly.
*-M*, *--multiplier* _multiplier_::
- On some architectures it is possible to alter the frequency at which the kernel delivers profiling interrupts to each CPU. This option allows you to set the frequency, as a multiplier of the system clock frequency, HZ. Linux 2.6.16 dropped multiplier support for most systems. This option also resets the profiling buffer, and requires superuser privileges.
+On some architectures it is possible to alter the frequency at which the kernel delivers profiling interrupts to each CPU. This option allows you to set the frequency, as a multiplier of the system clock frequency, HZ. Linux 2.6.16 dropped multiplier support for most systems. This option also resets the profiling buffer, and requires superuser privileges.
*-p*, *--profile* _pro-file_::
- Specify a different profiling buffer, which by default is _/proc/profile_. Using a different pro-file is useful if you want to `freeze' the kernel profiling at some time and read it later. The _/proc/profile_ file can be copied using *cat*(1) or *cp*(1). There is no more support for compressed profile buffers, like in *readprofile-1.1*, because the program needs to know the size of the buffer in advance.
+Specify a different profiling buffer, which by default is _/proc/profile_. Using a different pro-file is useful if you want to `freeze' the kernel profiling at some time and read it later. The _/proc/profile_ file can be copied using *cat*(1) or *cp*(1). There is no more support for compressed profile buffers, like in *readprofile-1.1*, because the program needs to know the size of the buffer in advance.
*-r*, *--reset*::
- Reset the profiling buffer. This can only be invoked by root, because _/proc/profile_ is readable by everybody but writable only by the superuser. However, you can make *readprofile* set-user-ID 0, in order to reset the buffer without gaining privileges.
+Reset the profiling buffer. This can only be invoked by root, because _/proc/profile_ is readable by everybody but writable only by the superuser. However, you can make *readprofile* set-user-ID 0, in order to reset the buffer without gaining privileges.
*-s, --counters*::
- Print individual counters within functions.
+Print individual counters within functions.
*-v*, *--verbose*::
- Verbose. The output is organized in four columns and filled with blanks. The first column is the RAM address of a kernel function, the second is the name of the function, the third is the number of clock ticks and the last is the normalized load.
+Verbose. The output is organized in four columns and filled with blanks. The first column is the RAM address of a kernel function, the second is the name of the function, the third is the number of clock ticks and the last is the normalized load.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== FILES
_/proc/profile_::
- A binary snapshot of the profiling buffer.
+A binary snapshot of the profiling buffer.
_/usr/src/linux/System.map_::
- The symbol table for the kernel.
+The symbol table for the kernel.
_/usr/src/linux/*_::
- The program being profiled :-)
+The program being profiled :-)
== BUGS
readprofile -av | less
....
-Browse a `frozen' profile buffer for a non current kernel:
+Browse a 'frozen' profile buffer for a non current kernel:
....
readprofile -p ~/profile.freeze -m /zImage.map.gz
== OPTIONS
*-n*, *--priority* _priority_::
- Specify the scheduling _priority_ to be used for the process, process group, or user. Use of the option *-n* or *--priority* is optional, but when used it must be the first argument.
+Specify the scheduling _priority_ to be used for the process, process group, or user. Use of the option *-n* or *--priority* is optional, but when used it must be the first argument.
*-g*, *--pgrp*::
- Interpret the succeeding arguments as process group IDs.
+Interpret the succeeding arguments as process group IDs.
*-p*, *--pid*::
- Interpret the succeeding arguments as process IDs (the default).
+Interpret the succeeding arguments as process IDs (the default).
*-u*, *--user*::
- Interpret the succeeding arguments as usernames or UIDs.
+Interpret the succeeding arguments as usernames or UIDs.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== FILES
_/etc/passwd_::
- to map user names to user IDs
+to map user names to user IDs
== NOTES
== OPTIONS
*-J*, *--json*::
- Use JSON output format.
+Use JSON output format.
*-n*, *--noheadings*::
- Do not print a header line.
+Do not print a header line.
*-o*, *--output*::
- Specify which output columns to print. Use *--help* to get a list of available columns.
+Specify which output columns to print. Use *--help* to get a list of available columns.
*--output-all*::
- Output all available columns.
+Output all available columns.
*-r*, *--raw*::
- Use the raw output format.
+Use the raw output format.
*--help*::
- Display help text and exit.
+Display help text and exit.
*--version*::
- Display version information and exit.
+Display version information and exit.
== COMMANDS
*help*::
- Display help text and exit.
+Display help text and exit.
*event*::
- Listen for rfkill events and display them on stdout.
+Listen for rfkill events and display them on stdout.
*list* [__id__|_type_ ...]::
- List the current state of all available devices. The command output format is deprecated, see the section DESCRIPTION. It is a good idea to check with *list* command _id_ or _type_ scope is appropriate before setting *block* or *unblock*. Special _all_ type string will match everything. Use of multiple _ID_ or _type_ arguments is supported.
+List the current state of all available devices. The command output format is deprecated, see the section DESCRIPTION. It is a good idea to check with *list* command _id_ or _type_ scope is appropriate before setting *block* or *unblock*. Special _all_ type string will match everything. Use of multiple _ID_ or _type_ arguments is supported.
**block id**|*type* [...]::
- Disable the corresponding device.
+Disable the corresponding device.
**unblock id**|*type* [...]::
- Enable the corresponding device. If the device is hard-blocked, for example via a hardware switch, it will remain unavailable though it is now soft-unblocked.
+Enable the corresponding device. If the device is hard-blocked, for example via a hardware switch, it will remain unavailable though it is now soft-unblocked.
**toggle id**|*type* [...]::
- Enable or disable the the corresponding device.
+Enable or disable the the corresponding device.
== EXAMPLE
....
== OPTIONS
*-A*, *--adjfile* _file_::
- Specify an alternative path to the adjust file.
+Specify an alternative path to the adjust file.
*-a*, *--auto*::
- Read the clock mode (whether the hardware clock is set to UTC or local time) from the _adjtime_ file, where *hwclock*(8) stores that information. This is the default.
+Read the clock mode (whether the hardware clock is set to UTC or local time) from the _adjtime_ file, where *hwclock*(8) stores that information. This is the default.
*--date* _timestamp_::
- Set the wakeup time to the value of the timestamp. Format of the timestamp can be any of the following:
+Set the wakeup time to the value of the timestamp. Format of the timestamp can be any of the following:
[cols=",",]
|===
|===
*-d*, *--device* _device_::
- Use the specified _device_ instead of *rtc0* as realtime clock. This option is only relevant if your system has more than one RTC. You may specify *rtc1*, *rtc2*, ... here.
+Use the specified _device_ instead of *rtc0* as realtime clock. This option is only relevant if your system has more than one RTC. You may specify *rtc1*, *rtc2*, ... here.
*-l*, *--local*::
- Assume that the hardware clock is set to local time, regardless of the contents of the _adjtime_ file.
+Assume that the hardware clock is set to local time, regardless of the contents of the _adjtime_ file.
*--list-modes*::
- List available *--mode* option arguments.
+List available *--mode* option arguments.
*-m*, *--mode* _mode_::
- Go into the given standby state. Valid values for _mode_ are: +
- *standby*;;
- ACPI state S1. This state offers minimal, though real, power savings, while providing a very low-latency transition back to a working system. This is the default mode.
- *freeze*;;
- The processes are frozen, all the devices are suspended and all the processors idled. This state is a general state that does not need any platform-specific support, but it saves less power than Suspend-to-RAM, because the system is still in a running state. (Available since Linux 3.9.)
- *mem*;;
- ACPI state S3 (Suspend-to-RAM). This state offers significant power savings as everything in the system is put into a low-power state, except for memory, which is placed in self-refresh mode to retain its contents.
- *disk*;;
- ACPI state S4 (Suspend-to-disk). This state offers the greatest power savings, and can be used even in the absence of low-level platform support for power management. This state operates similarly to Suspend-to-RAM, but includes a final step of writing memory contents to disk.
- *off*;;
- ACPI state S5 (Poweroff). This is done by calling '/sbin/shutdown'. Not officially supported by ACPI, but it usually works.
- *no*;;
- Don't suspend, only set the RTC wakeup time.
- *on*;;
- Don't suspend, but read the RTC device until an alarm time appears. This mode is useful for debugging.
- *disable*;;
- Disable a previously set alarm.
- *show*;;
- Print alarm information in format: "alarm: off|on <time>". The time is in ctime() output format, e.g., "alarm: on Tue Nov 16 04:48:45 2010".
+Go into the given standby state. Valid values for _mode_ are:
+
+*standby*;;
+ACPI state S1. This state offers minimal, though real, power savings, while providing a very low-latency transition back to a working system. This is the default mode.
+
+*freeze*;;
+The processes are frozen, all the devices are suspended and all the processors idled. This state is a general state that does not need any platform-specific support, but it saves less power than Suspend-to-RAM, because the system is still in a running state. (Available since Linux 3.9.)
+
+*mem*;;
+ACPI state S3 (Suspend-to-RAM). This state offers significant power savings as everything in the system is put into a low-power state, except for memory, which is placed in self-refresh mode to retain its contents.
+
+*disk*;;
+ACPI state S4 (Suspend-to-disk). This state offers the greatest power savings, and can be used even in the absence of low-level platform support for power management. This state operates similarly to Suspend-to-RAM, but includes a final step of writing memory contents to disk.
+
+*off*;;
+ACPI state S5 (Poweroff). This is done by calling '/sbin/shutdown'. Not officially supported by ACPI, but it usually works.
+
+*no*;;
+Don't suspend, only set the RTC wakeup time.
+
+*on*;;
+Don't suspend, but read the RTC device until an alarm time appears. This mode is useful for debugging.
+
+*disable*;;
+Disable a previously set alarm.
+
+*show*;;
+Print alarm information in format: "alarm: off|on <time>". The time is in ctime() output format, e.g., "alarm: on Tue Nov 16 04:48:45 2010".
*-n*, *--dry-run*::
- This option does everything apart from actually setting up the alarm, suspending the system, or waiting for the alarm.
+This option does everything apart from actually setting up the alarm, suspending the system, or waiting for the alarm.
*-s*, *--seconds* _seconds_::
- Set the wakeup time to _seconds_ in the future from now.
+Set the wakeup time to _seconds_ in the future from now.
*-t*, *--time* _time_t_::
- Set the wakeup time to the absolute time _time_t_. _time_t_ is the time in seconds since 1970-01-01, 00:00 UTC. Use the *date*(1) tool to convert between human-readable time and _time_t_.
+Set the wakeup time to the absolute time _time_t_. _time_t_ is the time in seconds since 1970-01-01, 00:00 UTC. Use the *date*(1) tool to convert between human-readable time and _time_t_.
*-u*, *--utc*::
- Assume that the hardware clock is set to UTC (Universal Time Coordinated), regardless of the contents of the _adjtime_ file.
+Assume that the hardware clock is set to UTC (Universal Time Coordinated), regardless of the contents of the _adjtime_ file.
*-v*, *--verbose*::
- Be verbose.
+Be verbose.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== NOTES
== OPTIONS
*--list*::
- List the architectures that *setarch* knows about. Whether *setarch* can actually set each of these architectures depends on the running kernel.
+List the architectures that *setarch* knows about. Whether *setarch* can actually set each of these architectures depends on the running kernel.
*--uname-2.6*::
- Causes the _program_ to see a kernel version number beginning with 2.6. Turns on *UNAME26*.
+Causes the _program_ to see a kernel version number beginning with 2.6. Turns on *UNAME26*.
*-v*, *--verbose*::
- Be verbose.
+Be verbose.
*-3*, *--3gb*::
- Specifies _program_ should use a maximum of 3GB of address space. Supported on x86. Turns on *ADDR_LIMIT_3GB*.
+Specifies _program_ should use a maximum of 3GB of address space. Supported on x86. Turns on *ADDR_LIMIT_3GB*.
*--4gb*::
- This option has no effect. It is retained for backward compatibility only, and may be removed in future releases.
+This option has no effect. It is retained for backward compatibility only, and may be removed in future releases.
*-B*, *--32bit*::
- Limit the address space to 32 bits to emulate hardware. Supported on ARM and Alpha. Turns on *ADDR_LIMIT_32BIT*.
+Limit the address space to 32 bits to emulate hardware. Supported on ARM and Alpha. Turns on *ADDR_LIMIT_32BIT*.
*-F*, *--fdpic-funcptrs*::
- Treat user-space function pointers to signal handlers as pointers to address descriptors. This option has no effect on architectures that do not support *FDPIC* ELF binaries. In kernel v4.14 support is limited to ARM, Blackfin, Fujitsu FR-V, and SuperH CPU architectures.
+Treat user-space function pointers to signal handlers as pointers to address descriptors. This option has no effect on architectures that do not support *FDPIC* ELF binaries. In kernel v4.14 support is limited to ARM, Blackfin, Fujitsu FR-V, and SuperH CPU architectures.
*-I*, *--short-inode*::
- Obsolete bug emulation flag. Turns on *SHORT_INODE*.
+Obsolete bug emulation flag. Turns on *SHORT_INODE*.
*-L*, *--addr-compat-layout*::
- Provide legacy virtual address space layout. Use when the _program_ binary does not have *PT_GNU_STACK* ELF header. Turns on *ADDR_COMPAT_LAYOUT*.
+Provide legacy virtual address space layout. Use when the _program_ binary does not have *PT_GNU_STACK* ELF header. Turns on *ADDR_COMPAT_LAYOUT*.
*-R*, *--addr-no-randomize*::
- Disables randomization of the virtual address space. Turns on *ADDR_NO_RANDOMIZE*.
+Disables randomization of the virtual address space. Turns on *ADDR_NO_RANDOMIZE*.
*-S*, *--whole-seconds*::
- Obsolete bug emulation flag. Turns on *WHOLE_SECONDS*.
+Obsolete bug emulation flag. Turns on *WHOLE_SECONDS*.
*-T*, *--sticky-timeouts*::
- This makes *select*(2), *pselect*(2), and *ppoll*(2) system calls preserve the timeout value instead of modifying it to reflect the amount of time not slept when interrupted by a signal handler. Use when _program_ depends on this behavior. For more details see the timeout description in *select*(2) manual page. Turns on *STICKY_TIMEOUTS*.
+This makes *select*(2), *pselect*(2), and *ppoll*(2) system calls preserve the timeout value instead of modifying it to reflect the amount of time not slept when interrupted by a signal handler. Use when _program_ depends on this behavior. For more details see the timeout description in *select*(2) manual page. Turns on *STICKY_TIMEOUTS*.
*-X*, *--read-implies-exec*::
- If this is set then *mmap*(3p) *PROT_READ* will also add the *PROT_EXEC* bit - as expected by legacy x86 binaries. Notice that the ELF loader will automatically set this bit when it encounters a legacy binary. Turns on *READ_IMPLIES_EXEC*.
+If this is set then *mmap*(3p) *PROT_READ* will also add the *PROT_EXEC* bit - as expected by legacy x86 binaries. Notice that the ELF loader will automatically set this bit when it encounters a legacy binary. Turns on *READ_IMPLIES_EXEC*.
*-Z*, *--mmap-page-zero*::
- SVr4 bug emulation that will set *mmap*(3p) page zero as read-only. Use when _program_ depends on this behavior, and the source code is not available to be fixed. Turns on *MMAP_PAGE_ZERO*.
+SVr4 bug emulation that will set *mmap*(3p) page zero as read-only. Use when _program_ depends on this behavior, and the source code is not available to be fixed. Turns on *MMAP_PAGE_ZERO*.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== EXAMPLE
== AUTHORS
-mailto:sopwith@redhat.com[Elliot Lee] +
-mailto:jnovy@redhat.com[Jindrich Novy] +
+mailto:sopwith@redhat.com[Elliot Lee],
+mailto:jnovy@redhat.com[Jindrich Novy],
mailto:kzak@redhat.com[Karel Zak]
== SEE ALSO
== OPTIONS
*--clear-groups*::
- Clear supplementary groups.
+Clear supplementary groups.
*-d*, *--dump*::
- Dump the current privilege state. This option can be specified more than once to show extra, mostly useless, information. Incompatible with all other options.
+Dump the current privilege state. This option can be specified more than once to show extra, mostly useless, information. Incompatible with all other options.
*--groups* _group_...::
- Set supplementary groups. The argument is a comma-separated list of GIDs or names.
+Set supplementary groups. The argument is a comma-separated list of GIDs or names.
*--inh-caps* (*+*|*-*)_cap_...::
*--ambient-caps* (*+*|*-*)_cap_...::
*--bounding-set* (*+*|*-*)_cap_...::
- Set the inheritable capabilities, ambient capabilities or the capability bounding set. See *capabilities*(7). The argument is a comma-separated list of **+**__cap__ and **-**__cap__ entries, which add or remove an entry respectively. _cap_ can either be a human-readable name as seen in *capabilities*(7) without the _cap__ prefix or of the format *cap_N*, where _N_ is the internal capability index used by Linux. *+all* and *-all* can be used to add or remove all caps. +
- {nbsp} +
- The set of capabilities starts out as the current inheritable set for *--inh-caps*, the current ambient set for *--ambient-caps* and the current bounding set for *--bounding-set*. +
- {nbsp} +
- Note the following restrictions (detailed in *capabilities*(7)) regarding modifications to these capability sets: +
- {nbsp} +
- * A capability can be added to the inheritable set only if it is currently present in the bounding set.
- * A capability can be added to the ambient set only if it is currently present in both the permitted and inheritable sets.
- * Notwithstanding the syntax offered by *setpriv*, the kernel does not permit capabilities to be added to the bounding set. +
- {nbsp} +
- If you drop a capability from the bounding set without also dropping it from the inheritable set, you are likely to become confused. Do not do that.
+Set the inheritable capabilities, ambient capabilities or the capability bounding set. See *capabilities*(7). The argument is a comma-separated list of **+**__cap__ and **-**__cap__ entries, which add or remove an entry respectively. _cap_ can either be a human-readable name as seen in *capabilities*(7) without the _cap__ prefix or of the format *cap_N*, where _N_ is the internal capability index used by Linux. *+all* and *-all* can be used to add or remove all caps.
++
+The set of capabilities starts out as the current inheritable set for *--inh-caps*, the current ambient set for *--ambient-caps* and the current bounding set for *--bounding-set*.
++
+Note the following restrictions (detailed in *capabilities*(7)) regarding modifications to these capability sets:
+
+* A capability can be added to the inheritable set only if it is currently present in the bounding set.
+* A capability can be added to the ambient set only if it is currently present in both the permitted and inheritable sets.
+* Notwithstanding the syntax offered by *setpriv*, the kernel does not permit capabilities to be added to the bounding set.
+
+If you drop a capability from the bounding set without also dropping it from the inheritable set, you are likely to become confused. Do not do that.
*--keep-groups*::
- Preserve supplementary groups. Only useful in conjunction with *--rgid*, *--egid*, or *--regid*.
+Preserve supplementary groups. Only useful in conjunction with *--rgid*, *--egid*, or *--regid*.
*--init-groups*::
- Initialize supplementary groups using initgroups3. Only useful in conjunction with *--ruid* or *--reuid*.
+Initialize supplementary groups using initgroups3. Only useful in conjunction with *--ruid* or *--reuid*.
*--list-caps*::
- List all known capabilities. This option must be specified alone.
+List all known capabilities. This option must be specified alone.
*--no-new-privs*::
- Set the _no_new_privs_ bit. With this bit set, *execve*(2) will not grant new privileges. For example, the set-user-ID and set-group-ID bits as well as file capabilities will be disabled. (Executing binaries with these bits set will still work, but they will not gain privileges. Certain LSMs, especially AppArmor, may result in failures to execute certain programs.) This bit is inherited by child processes and cannot be unset. See *prctl*(2) and _Documentation/prctl/no_new_privs.txt_ in the Linux kernel source. +
- {nbsp} +
- The _no_new_privs_ bit is supported since Linux 3.5.
+Set the _no_new_privs_ bit. With this bit set, *execve*(2) will not grant new privileges. For example, the set-user-ID and set-group-ID bits as well as file capabilities will be disabled. (Executing binaries with these bits set will still work, but they will not gain privileges. Certain LSMs, especially AppArmor, may result in failures to execute certain programs.) This bit is inherited by child processes and cannot be unset. See *prctl*(2) and _Documentation/prctl/no_new_privs.txt_ in the Linux kernel source.
++
+The _no_new_privs_ bit is supported since Linux 3.5.
*--rgid* _gid_, *--egid* _gid_, *--regid* _gid_::
- Set the real, effective, or both GIDs. The _gid_ argument can be given as a textual group name. +
- {nbsp} +
- For safety, you must specify one of *--clear-groups*, *--groups*, *--keep-groups*, or *--init-groups* if you set any primary _gid_.
+Set the real, effective, or both GIDs. The _gid_ argument can be given as a textual group name.
++
+For safety, you must specify one of *--clear-groups*, *--groups*, *--keep-groups*, or *--init-groups* if you set any primary _gid_.
*--ruid* _uid_, *--euid* _uid_, *--reuid* _uid_::
- Set the real, effective, or both UIDs. The _uid_ argument can be given as a textual login name. +
- {nbsp} +
- Setting a _uid_ or _gid_ does not change capabilities, although the exec call at the end might change capabilities. This means that, if you are root, you probably want to do something like: +
- {nbsp} +
- *setpriv --reuid=1000 --regid=1000 --inh-caps=-all*
+Set the real, effective, or both UIDs. The _uid_ argument can be given as a textual login name.
++
+Setting a _uid_ or _gid_ does not change capabilities, although the exec call at the end might change capabilities. This means that, if you are root, you probably want to do something like:
++
+*setpriv --reuid=1000 --regid=1000 --inh-caps=-all*
*--securebits* (**+**|*-*)__securebit__...::
- Set or clear securebits. The argument is a comma-separated list. The valid securebits are _noroot_, _noroot_locked_, _no_setuid_fixup_, _no_setuid_fixup_locked_, and _keep_caps_locked_. _keep_caps_ is cleared by *execve*(2) and is therefore not allowed.
+Set or clear securebits. The argument is a comma-separated list. The valid securebits are _noroot_, _noroot_locked_, _no_setuid_fixup_, _no_setuid_fixup_locked_, and _keep_caps_locked_. _keep_caps_ is cleared by *execve*(2) and is therefore not allowed.
**--pdeathsig keep**|**clear**|*<signal>*::
- Keep, clear or set the parent death signal. Some LSMs, most notably SELinux and AppArmor, clear the signal when the process' credentials change. Using *--pdeathsig keep* will restore the parent death signal after changing credentials to remedy that situation.
+Keep, clear or set the parent death signal. Some LSMs, most notably SELinux and AppArmor, clear the signal when the process' credentials change. Using *--pdeathsig keep* will restore the parent death signal after changing credentials to remedy that situation.
*--selinux-label* _label_::
- Request a particular SELinux transition (using a transition on exec, not dyntrans). This will fail and cause *setpriv* to abort if SELinux is not in use, and the transition may be ignored or cause *execve*(2) to fail at SELinux's whim. (In particular, this is unlikely to work in conjunction with _no_new_privs_.) This is similar to *runcon*(1).
+Request a particular SELinux transition (using a transition on exec, not dyntrans). This will fail and cause *setpriv* to abort if SELinux is not in use, and the transition may be ignored or cause *execve*(2) to fail at SELinux's whim. (In particular, this is unlikely to work in conjunction with _no_new_privs_.) This is similar to *runcon*(1).
*--apparmor-profile* _profile_::
- Request a particular AppArmor profile (using a transition on exec). This will fail and cause *setpriv* to abort if AppArmor is not in use, and the transition may be ignored or cause *execve*(2) to fail at AppArmor's whim.
+Request a particular AppArmor profile (using a transition on exec). This will fail and cause *setpriv* to abort if AppArmor is not in use, and the transition may be ignored or cause *execve*(2) to fail at AppArmor's whim.
*--reset-env*::
- Clears all the environment variables except *TERM*; initializes the environment variables *HOME*, *SHELL*, *USER*, *LOGNAME* according to the user's passwd entry; sets *PATH* to _/usr/local/bin:/bin:/usr/bin_ for a regular user and to _/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin_ for root. +
- {nbsp} +
- The environment variable *PATH* may be different on systems where _/bin_ and _/sbin_ are merged into _/usr_. The environment variable *SHELL* defaults to */bin/sh* if none is given in the user's passwd entry.
+Clears all the environment variables except *TERM*; initializes the environment variables *HOME*, *SHELL*, *USER*, *LOGNAME* according to the user's passwd entry; sets *PATH* to _/usr/local/bin:/bin:/usr/bin_ for a regular user and to _/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin_ for root.
++
+The environment variable *PATH* may be different on systems where _/bin_ and _/sbin_ are merged into _/usr_. The environment variable *SHELL* defaults to */bin/sh* if none is given in the user's passwd entry.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== NOTES
== OPTIONS
*-c*, *--ctty*::
- Set the controlling terminal to the current one.
+Set the controlling terminal to the current one.
*-f*, *--fork*::
- Always create a new process.
+Always create a new process.
*-w*, *--wait*::
- Wait for the execution of the program to end, and return the exit status of this program as the exit status of *setsid*.
+Wait for the execution of the program to end, and return the exit status of this program as the exit status of *setsid*.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== AUTHORS
== OPTIONS
*-a*, *--all*::
- All devices marked as "swap" in _/etc/fstab_ are made available, except for those with the "noauto" option. Devices that are already being used as swap are silently skipped.
+All devices marked as "swap" in _/etc/fstab_ are made available, except for those with the "noauto" option. Devices that are already being used as swap are silently skipped.
*-d*, *--discard*[**=**__policy__]::
- Enable swap discards, if the swap backing device supports the discard or trim operation. This may improve performance on some Solid State Devices, but often it does not. The option allows one to select between two available swap discard policies:
+Enable swap discards, if the swap backing device supports the discard or trim operation. This may improve performance on some Solid State Devices, but often it does not. The option allows one to select between two available swap discard policies:
-*--discard=once*::: to perform a single-time discard operation for the whole swap area at swapon; or +
-*--discard=pages*::: to asynchronously discard freed swap pages before they are available for reuse. +
+*--discard=once*;;
+to perform a single-time discard operation for the whole swap area at swapon; or
+*--discard=pages*;;
+to asynchronously discard freed swap pages before they are available for reuse.
+
++
If no policy is selected, the default behavior is to enable both discard types. The _/etc/fstab_ mount options *discard*, *discard=once*, or *discard=pages* may also be used to enable discard flags.
*-e*, *--ifexists*::
- Silently skip devices that do not exist. The _/etc/fstab_ mount option *nofail* may also be used to skip non-existing device.
+Silently skip devices that do not exist. The _/etc/fstab_ mount option *nofail* may also be used to skip non-existing device.
*-f*, *--fixpgsz*::
- Reinitialize (exec mkswap) the swap space if its page size does not match that of the current running kernel. *mkswap*(8) initializes the whole device and does not check for bad blocks.
+Reinitialize (exec mkswap) the swap space if its page size does not match that of the current running kernel. *mkswap*(8) initializes the whole device and does not check for bad blocks.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
*-L* _label_::
- Use the partition that has the specified _label_. (For this, access to _/proc/partitions_ is needed.)
+Use the partition that has the specified _label_. (For this, access to _/proc/partitions_ is needed.)
*-o*, *--options* _opts_::
- Specify swap options by an fstab-compatible comma-separated string. For example: +
- {nbsp} +
- *swapon -o pri=1,discard=pages,nofail /dev/sda2* +
- {nbsp} +
- The _opts_ string is evaluated last and overrides all other command line options.
+Specify swap options by an fstab-compatible comma-separated string. For example:
++
+*swapon -o pri=1,discard=pages,nofail /dev/sda2*
++
+The _opts_ string is evaluated last and overrides all other command line options.
*-p*, *--priority* _priority_::
- Specify the priority of the swap device. _priority_ is a value between -1 and 32767. Higher numbers indicate higher priority. See *swapon*(2) for a full description of swap priorities. Add **pri=**__value__ to the option field of _/etc/fstab_ for use with *swapon -a*. When no priority is defined, it defaults to -1.
+Specify the priority of the swap device. _priority_ is a value between -1 and 32767. Higher numbers indicate higher priority. See *swapon*(2) for a full description of swap priorities. Add **pri=**__value__ to the option field of _/etc/fstab_ for use with *swapon -a*. When no priority is defined, it defaults to -1.
*-s*, *--summary*::
- Display swap usage summary by device. Equivalent to *cat /proc/swaps*. This output format is DEPRECATED in favour of *--show* that provides better control on output data.
+Display swap usage summary by device. Equivalent to *cat /proc/swaps*. This output format is DEPRECATED in favour of *--show* that provides better control on output data.
*--show*[**=**__column__...]::
- Display a definable table of swap areas. See the *--help* output for a list of available columns.
+Display a definable table of swap areas. See the *--help* output for a list of available columns.
*--output-all*::
- Output all available columns.
+Output all available columns.
*--noheadings*::
- Do not print headings when displaying *--show* output.
+Do not print headings when displaying *--show* output.
*--raw*::
- Display *--show* output without aligning table columns.
+Display *--show* output without aligning table columns.
*--bytes*::
- Display swap size in bytes in *--show* output instead of in user-friendly units.
+Display swap size in bytes in *--show* output instead of in user-friendly units.
*-U* _uuid_::
- Use the partition that has the specified _uuid_.
+Use the partition that has the specified _uuid_.
*-v*, *--verbose*::
- Be verbose.
+Be verbose.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
== EXIT STATUS
*swapoff* has the following exit status values since v2.36:
*0*::
- success
+success
*2*::
- system has insufficient memory to stop swapping (OOM)
+system has insufficient memory to stop swapping (OOM)
*4*::
- swapoff syscall failed for another reason
+swapoff syscall failed for another reason
*8*::
- non-swapoff syscall system error (out of memory, ...)
+non-swapoff syscall system error (out of memory, ...)
*16*::
- usage or syntax error
+usage or syntax error
*32*::
- all swapoff failed on *--all*
+all swapoff failed on *--all*
*64*::
- some swapoff succeeded on *--all* +
- {nbsp} +
- The command *swapoff --all* returns 0 (all succeeded), 32 (all failed), or 64 (some failed, some succeeded). +
- {nbsp} +
- The old versions before v2.36 has no documented exit status, 0 means success in all versions.
+some swapoff succeeded on *--all*
+
+The command *swapoff --all* returns 0 (all succeeded), 32 (all failed), or 64 (some failed, some succeeded).
++
+The old versions before v2.36 has no documented exit status, 0 means success in all versions.
== ENVIRONMENT
LIBMOUNT_DEBUG=all::
- enables *libmount* debug output.
+enables *libmount* debug output.
LIBBLKID_DEBUG=all::
- enables *libblkid* debug output.
+enables *libblkid* debug output.
== FILES
_/dev/sd??_::
- standard paging devices
+standard paging devices
_/etc/fstab_::
- ascii filesystem description table
+ascii filesystem description table
== NOTES
== OPTIONS
*-h, --help*::
- Display help text and exit.
+Display help text and exit.
*-V, --version*::
- Display version information and exit.
+Display version information and exit.
== EXIT STATUS
== AUTHORS
-mailto:pjones@redhat.com[Peter Jones] +
-mailto:katzj@redhat.com[Jeremy Katz] +
+mailto:pjones@redhat.com[Peter Jones],
+mailto:katzj@redhat.com[Jeremy Katz],
mailto:kzak@redhat.com[Karel Zak]
== SEE ALSO
== OPTIONS
*-i*, *--irq* _argument_::
- specifies the IRQ to use for the parallel port in question. If this is set to something non-zero, *-t* and *-c* have no effect. If your port does not use interrupts, this option will make printing stop. The command *tunelp -i 0* restores non-interrupt driven (polling) action, and your printer should work again. If your parallel port does support interrupts, interrupt-driven printing should be somewhat faster and efficient, and will probably be desirable. +
- {nbsp} +
- NOTE: This option will have no effect with kernel 2.1.131 or later since the irq is handled by the parport driver. You can change the parport irq for example via _/proc/parport/*/irq_. Read _/usr/src/linux/Documentation/admin-guide/parport.rst_ for more details on parport.
+specifies the IRQ to use for the parallel port in question. If this is set to something non-zero, *-t* and *-c* have no effect. If your port does not use interrupts, this option will make printing stop. The command *tunelp -i 0* restores non-interrupt driven (polling) action, and your printer should work again. If your parallel port does support interrupts, interrupt-driven printing should be somewhat faster and efficient, and will probably be desirable.
++
+*NOTE*: This option will have no effect with kernel 2.1.131 or later since the irq is handled by the parport driver. You can change the parport irq for example via _/proc/parport/*/irq_. Read _/usr/src/linux/Documentation/admin-guide/parport.rst_ for more details on parport.
*-t*, *--time* _milliseconds_::
- is the amount of time in jiffies that the driver waits if the printer doesn't take a character for the number of tries dictated by the *-c* parameter. 10 is the default value. If you want fastest possible printing, and don't care about system load, you may set this to 0. If you don't care how fast your printer goes, or are printing text on a slow printer with a buffer, then 500 (5 seconds) should be fine, and will give you very low system load. This value generally should be lower for printing graphics than text, by a factor of approximately 10, for best performance.
+is the amount of time in jiffies that the driver waits if the printer doesn't take a character for the number of tries dictated by the *-c* parameter. 10 is the default value. If you want fastest possible printing, and don't care about system load, you may set this to 0. If you don't care how fast your printer goes, or are printing text on a slow printer with a buffer, then 500 (5 seconds) should be fine, and will give you very low system load. This value generally should be lower for printing graphics than text, by a factor of approximately 10, for best performance.
*-c*, *--chars* _characters_::
- is the number of times to try to output a character to the printer before sleeping for *-t* _TIME_. It is the number of times around a loop that tries to send a character to the printer. 120 appears to be a good value for most printers in polling mode. 1000 is the default, because there are some printers that become jerky otherwise, but you _must_ set this to `1' to handle the maximal CPU efficiency if you are using interrupts. If you have a very fast printer, a value of 10 might make more sense even if in polling mode. If you have a _really_ old printer, you can increase this further. +
- {nbsp} +
- Setting *-t* _TIME_ to 0 is equivalent to setting *-c* _CHARS_ to infinity.
+is the number of times to try to output a character to the printer before sleeping for *-t* _TIME_. It is the number of times around a loop that tries to send a character to the printer. 120 appears to be a good value for most printers in polling mode. 1000 is the default, because there are some printers that become jerky otherwise, but you _must_ set this to '1' to handle the maximal CPU efficiency if you are using interrupts. If you have a very fast printer, a value of 10 might make more sense even if in polling mode. If you have a _really_ old printer, you can increase this further.
++
+Setting *-t* _TIME_ to 0 is equivalent to setting *-c* _CHARS_ to infinity.
*-w*, *--wait* _milliseconds_::
- is the number of usec we wait while playing with the strobe signal. While most printers appear to be able to deal with an extremely short strobe, some printers demand a longer one. Increasing this from the default 1 may make it possible to print with those printers. This may also make it possible to use longer cables. It's also possible to decrease this value to 0 if your printer is fast enough or your machine is slow enough.
+is the number of usec we wait while playing with the strobe signal. While most printers appear to be able to deal with an extremely short strobe, some printers demand a longer one. Increasing this from the default 1 may make it possible to print with those printers. This may also make it possible to use longer cables. It's also possible to decrease this value to 0 if your printer is fast enough or your machine is slow enough.
*-a*, *--abort* _<on|off>_::
- This is whether to abort on printer error - the default is not to. If you are sitting at your computer, you probably want to be able to see an error and fix it, and have the printer go on printing. On the other hand, if you aren't, you might rather that your printer spooler find out that the printer isn't ready, quit trying, and send you mail about it. The choice is yours.
+This is whether to abort on printer error - the default is not to. If you are sitting at your computer, you probably want to be able to see an error and fix it, and have the printer go on printing. On the other hand, if you aren't, you might rather that your printer spooler find out that the printer isn't ready, quit trying, and send you mail about it. The choice is yours.
*-o*, *--check-status* _<on|off>_::
- This option is much like *-a*. It makes any *open*(2) of this device check to see that the device is on-line and not reporting any out of paper or other errors. This is the correct setting for most versions of *lpd*.
+This option is much like *-a*. It makes any *open*(2) of this device check to see that the device is on-line and not reporting any out of paper or other errors. This is the correct setting for most versions of *lpd*.
*-C*, *--careful* _<on|off>_::
- This option adds extra ("careful") error checking. When this option is on, the printer driver will ensure that the printer is on-line and not reporting any out of paper or other errors before sending data. This is particularly useful for printers that normally appear to accept data when turned off. +
- {nbsp} +
- *NOTE*: This option is obsolete because it's the default in 2.1.131 kernel or later.
+This option adds extra ("careful") error checking. When this option is on, the printer driver will ensure that the printer is on-line and not reporting any out of paper or other errors before sending data. This is particularly useful for printers that normally appear to accept data when turned off.
++
+*NOTE*: This option is obsolete because it's the default in 2.1.131 kernel or later.
*-s*, *--status*::
- This option returns the current printer status, both as a decimal number from 0..255, and as a list of active flags. When this option is specified, *-q* off, turning off the display of the current IRQ, is implied.
+This option returns the current printer status, both as a decimal number from 0..255, and as a list of active flags. When this option is specified, *-q* off, turning off the display of the current IRQ, is implied.
*-r*, *--reset*::
- This option resets the port. It requires a Linux kernel version of 1.1.80 or later.
+This option resets the port. It requires a Linux kernel version of 1.1.80 or later.
*-q*, *--print-irq* _<on|off>_::
- This option sets printing the display of the current IRQ setting.
+This option sets printing the display of the current IRQ setting.
== FILES
-_/dev/lp?_ +
+_/dev/lp?_,
_/proc/parport/*/*_
== NOTES
== OPTIONS
*-a*, *--all*::
- All of the filesystems described in _/proc/self/mountinfo_ (or in deprecated _/etc/mtab_) are unmounted, except the proc, devfs, devpts, sysfs, rpc_pipefs and nfsd filesystems. This list of the filesystems may be replaced by *--types* umount option.
+All of the filesystems described in _/proc/self/mountinfo_ (or in deprecated _/etc/mtab_) are unmounted, except the proc, devfs, devpts, sysfs, rpc_pipefs and nfsd filesystems. This list of the filesystems may be replaced by *--types* umount option.
*-A*, *--all-targets*::
- Unmount all mountpoints in the current mount namespace for the specified filesystem. The filesystem can be specified by one of the mountpoints or the device name (or UUID, etc.). When this option is used together with *--recursive*, then all nested mounts within the filesystem are recursively unmounted. This option is only supported on systems where _/etc/mtab_ is a symlink to _/proc/mounts_.
+Unmount all mountpoints in the current mount namespace for the specified filesystem. The filesystem can be specified by one of the mountpoints or the device name (or UUID, etc.). When this option is used together with *--recursive*, then all nested mounts within the filesystem are recursively unmounted. This option is only supported on systems where _/etc/mtab_ is a symlink to _/proc/mounts_.
*-c*, *--no-canonicalize*::
- Do not canonicalize paths. The paths canonicalization is based on *stat*(2) and *readlink*(2) system calls. These system calls may hang in some cases (for example on NFS if server is not available). The option has to be used with canonical path to the mount point. +
- {nbsp} +
- This option is silently ignored by *umount* for non-root users. +
- {nbsp} +
- For more details about this option see the *mount*(8) man page. Note that *umount* does not pass this option to the **/sbin/umount.**__type__ helpers.
+Do not canonicalize paths. The paths canonicalization is based on *stat*(2) and *readlink*(2) system calls. These system calls may hang in some cases (for example on NFS if server is not available). The option has to be used with canonical path to the mount point.
++
+This option is silently ignored by *umount* for non-root users.
++
+For more details about this option see the *mount*(8) man page. Note that *umount* does not pass this option to the **/sbin/umount.**__type__ helpers.
*-d*, *--detach-loop*::
- When the unmounted device was a loop device, also free this loop device. This option is unnecessary for devices initialized by *mount*(8), in this case "autoclear" functionality is enabled by default.
+When the unmounted device was a loop device, also free this loop device. This option is unnecessary for devices initialized by *mount*(8), in this case "autoclear" functionality is enabled by default.
*--fake*::
- Causes everything to be done except for the actual system call or umount helper execution; this 'fakes' unmounting the filesystem. It can be used to remove entries from the deprecated _/etc/mtab_ that were unmounted earlier with the *-n* option.
+Causes everything to be done except for the actual system call or umount helper execution; this 'fakes' unmounting the filesystem. It can be used to remove entries from the deprecated _/etc/mtab_ that were unmounted earlier with the *-n* option.
*-f*, *--force*::
- Force an unmount (in case of an unreachable NFS system). +
- {nbsp} +
- Note that this option does not guarantee that umount command does not hang. It's strongly recommended to use absolute paths without symlinks to avoid unwanted readlink and stat system calls on unreachable NFS in *umount*.
+Force an unmount (in case of an unreachable NFS system).
++
+Note that this option does not guarantee that umount command does not hang. It's strongly recommended to use absolute paths without symlinks to avoid unwanted readlink and stat system calls on unreachable NFS in *umount*.
*-i*, *--internal-only*::
- Do not call the **/sbin/umount.**__filesystem__ helper even if it exists. By default such a helper program is called if it exists.
+Do not call the **/sbin/umount.**__filesystem__ helper even if it exists. By default such a helper program is called if it exists.
*-l*, *--lazy*::
- Lazy unmount. Detach the filesystem from the file hierarchy now, and clean up all references to this filesystem as soon as it is not busy anymore. +
- {nbsp} +
- A system reboot would be expected in near future if you're going to use this option for network filesystem or local filesystem with submounts. The recommended use-case for *umount -l* is to prevent hangs on shutdown due to an unreachable network share where a normal umount will hang due to a downed server or a network partition. Remounts of the share will not be possible.
+Lazy unmount. Detach the filesystem from the file hierarchy now, and clean up all references to this filesystem as soon as it is not busy anymore.
++
+A system reboot would be expected in near future if you're going to use this option for network filesystem or local filesystem with submounts. The recommended use-case for *umount -l* is to prevent hangs on shutdown due to an unreachable network share where a normal umount will hang due to a downed server or a network partition. Remounts of the share will not be possible.
*-N*, *--namespace* _ns_::
- Perform umount in the mount namespace specified by _ns_. _ns_ is either PID of process running in that namespace or special file representing that namespace. +
- {nbsp} +
- *umount* switches to the namespace when it reads _/etc/fstab_, writes _/etc/mtab_ (or writes to _/run/mount_) and calls *umount*(2) system call, otherwise it runs in the original namespace. It means that the target mount namespace does not have to contain any libraries or other requirements necessary to execute *umount*(2) command. +
- {nbsp} +
- See *mount_namespaces*(7) for more information.
+Perform umount in the mount namespace specified by _ns_. _ns_ is either PID of process running in that namespace or special file representing that namespace.
++
+*umount* switches to the namespace when it reads _/etc/fstab_, writes _/etc/mtab_ (or writes to _/run/mount_) and calls *umount*(2) system call, otherwise it runs in the original namespace. It means that the target mount namespace does not have to contain any libraries or other requirements necessary to execute *umount*(2) command.
++
+See *mount_namespaces*(7) for more information.
*-n*, *--no-mtab*::
- Unmount without writing in _/etc/mtab_.
+Unmount without writing in _/etc/mtab_.
*-O*, *--test-opts* _option_...::
- Unmount only the filesystems that have the specified option set in _/etc/fstab_. More than one option may be specified in a comma-separated list. Each option can be prefixed with *no* to indicate that no action should be taken for this option.
+Unmount only the filesystems that have the specified option set in _/etc/fstab_. More than one option may be specified in a comma-separated list. Each option can be prefixed with *no* to indicate that no action should be taken for this option.
*-q*, *--quiet*::
- Suppress "not mounted" error messages.
+Suppress "not mounted" error messages.
*-R*, *--recursive*::
- Recursively unmount each specified directory. Recursion for each directory will stop if any unmount operation in the chain fails for any reason. The relationship between mountpoints is determined by _/proc/self/mountinfo_ entries. The filesystem must be specified by mountpoint path; a recursive unmount by device name (or UUID) is unsupported. Since version 2.37 it umounts also all over-mounted filesystems (more filesystems on the same mountpoint).
+Recursively unmount each specified directory. Recursion for each directory will stop if any unmount operation in the chain fails for any reason. The relationship between mountpoints is determined by _/proc/self/mountinfo_ entries. The filesystem must be specified by mountpoint path; a recursive unmount by device name (or UUID) is unsupported. Since version 2.37 it umounts also all over-mounted filesystems (more filesystems on the same mountpoint).
*-r*, *--read-only*::
- When an unmount fails, try to remount the filesystem read-only.
+When an unmount fails, try to remount the filesystem read-only.
*-t*, *--types* _type_...::
- Indicate that the actions should only be taken on filesystems of the specified _type_. More than one type may be specified in a comma-separated list. The list of filesystem types can be prefixed with *no* to indicate that no action should be taken for all of the mentioned types. Note that *umount* reads information about mounted filesystems from kernel (_/proc/mounts_) and filesystem names may be different than filesystem names used in the _/etc/fstab_ (e.g., "nfs4" vs. "nfs").
+Indicate that the actions should only be taken on filesystems of the specified _type_. More than one type may be specified in a comma-separated list. The list of filesystem types can be prefixed with *no* to indicate that no action should be taken for all of the mentioned types. Note that *umount* reads information about mounted filesystems from kernel (_/proc/mounts_) and filesystem names may be different than filesystem names used in the _/etc/fstab_ (e.g., "nfs4" vs. "nfs").
*-v*, *--verbose*::
- Verbose mode.
+Verbose mode.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== NON-SUPERUSER UMOUNTS
== ENVIRONMENT
LIBMOUNT_FSTAB=<path>::
- overrides the default location of the fstab file (ignored for suid)
+overrides the default location of the fstab file (ignored for suid)
LIBMOUNT_MTAB=<path>::
- overrides the default location of the mtab file (ignored for suid)
+overrides the default location of the mtab file (ignored for suid)
LIBMOUNT_DEBUG=all::
- enables *libmount* debug output
+enables *libmount* debug output
== FILES
_/etc/mtab_::
- table of mounted filesystems (deprecated and usually replaced by symlink to _/proc/mounts_)
+table of mounted filesystems (deprecated and usually replaced by symlink to _/proc/mounts_)
_/etc/fstab_::
- table of known filesystems
+table of known filesystems
_/proc/self/mountinfo_::
- table of mounted filesystems generated by kernel.
+table of mounted filesystems generated by kernel.
== HISTORY
The following types of namespaces can be created with *unshare*:
*mount namespace*::
- Mounting and unmounting filesystems will not affect the rest of the system, except for filesystems which are explicitly marked as shared (with *mount --make-shared*; see _/proc/self/mountinfo_ or *findmnt -o+PROPAGATION* for the *shared* flags). For further details, see *mount_namespaces*(7). +
- {nbsp} +
- *unshare* since util-linux version 2.27 automatically sets propagation to *private* in a new mount namespace to make sure that the new namespace is really unshared. It's possible to disable this feature with option *--propagation unchanged*. Note that *private* is the kernel default.
+Mounting and unmounting filesystems will not affect the rest of the system, except for filesystems which are explicitly marked as shared (with *mount --make-shared*; see _/proc/self/mountinfo_ or *findmnt -o+PROPAGATION* for the *shared* flags). For further details, see *mount_namespaces*(7).
++
+*unshare* since util-linux version 2.27 automatically sets propagation to *private* in a new mount namespace to make sure that the new namespace is really unshared. It's possible to disable this feature with option *--propagation unchanged*. Note that *private* is the kernel default.
*UTS namespace*::
- Setting hostname or domainname will not affect the rest of the system. For further details, see *uts_namespaces*(7).
+Setting hostname or domainname will not affect the rest of the system. For further details, see *uts_namespaces*(7).
*IPC namespace*::
- The process will have an independent namespace for POSIX message queues as well as System V message queues, semaphore sets and shared memory segments. For further details, see *ipc_namespaces*(7).
+The process will have an independent namespace for POSIX message queues as well as System V message queues, semaphore sets and shared memory segments. For further details, see *ipc_namespaces*(7).
*network namespace*::
- The process will have independent IPv4 and IPv6 stacks, IP routing tables, firewall rules, the _/proc/net_ and _/sys/class/net_ directory trees, sockets, etc. For further details, see *network_namespaces*(7).
+The process will have independent IPv4 and IPv6 stacks, IP routing tables, firewall rules, the _/proc/net_ and _/sys/class/net_ directory trees, sockets, etc. For further details, see *network_namespaces*(7).
*PID namespace*::
- Children will have a distinct set of PID-to-process mappings from their parent. For further details, see *pid_namespaces*(7).
+Children will have a distinct set of PID-to-process mappings from their parent. For further details, see *pid_namespaces*(7).
*cgroup namespace*::
- The process will have a virtualized view of _/proc/self/cgroup_, and new cgroup mounts will be rooted at the namespace cgroup root. For further details, see *cgroup_namespaces*(7).
+The process will have a virtualized view of _/proc/self/cgroup_, and new cgroup mounts will be rooted at the namespace cgroup root. For further details, see *cgroup_namespaces*(7).
*user namespace*::
- The process will have a distinct set of UIDs, GIDs and capabilities. For further details, see *user_namespaces*(7).
+The process will have a distinct set of UIDs, GIDs and capabilities. For further details, see *user_namespaces*(7).
*time namespace*::
- The process can have a distinct view of *CLOCK_MONOTONIC* and/or *CLOCK_BOOTTIME* which can be changed using _/proc/self/timens_offsets_. For further details, see *time_namespaces*(7).
+The process can have a distinct view of *CLOCK_MONOTONIC* and/or *CLOCK_BOOTTIME* which can be changed using _/proc/self/timens_offsets_. For further details, see *time_namespaces*(7).
== OPTIONS
*-i*, *--ipc*[**=**__file__]::
- Unshare the IPC namespace. If _file_ is specified, then a persistent namespace is created by a bind mount.
+Unshare the IPC namespace. If _file_ is specified, then a persistent namespace is created by a bind mount.
*-m*, *--mount*[**=**__file__]::
- Unshare the mount namespace. If _file_ is specified, then a persistent namespace is created by a bind mount. Note that _file_ must be located on a mount whose propagation type is not *shared* (or an error results). Use the command *findmnt -o+PROPAGATION* when not sure about the current setting. See also the examples below.
+Unshare the mount namespace. If _file_ is specified, then a persistent namespace is created by a bind mount. Note that _file_ must be located on a mount whose propagation type is not *shared* (or an error results). Use the command *findmnt -o+PROPAGATION* when not sure about the current setting. See also the examples below.
*-n*, *--net*[**=**__file__]::
- Unshare the network namespace. If _file_ is specified, then a persistent namespace is created by a bind mount.
+Unshare the network namespace. If _file_ is specified, then a persistent namespace is created by a bind mount.
*-p*, *--pid*[**=**__file__]::
- Unshare the PID namespace. If _file_ is specified, then a persistent namespace is created by a bind mount. (Creation of a persistent PID namespace will fail if the *--fork* option is not also specified.) +
- {nbsp} +
- See also the *--fork* and *--mount-proc* options.
+Unshare the PID namespace. If _file_ is specified, then a persistent namespace is created by a bind mount. (Creation of a persistent PID namespace will fail if the *--fork* option is not also specified.)
++
+See also the *--fork* and *--mount-proc* options.
*-u*, *--uts*[**=**__file__]::
- Unshare the UTS namespace. If _file_ is specified, then a persistent namespace is created by a bind mount.
+Unshare the UTS namespace. If _file_ is specified, then a persistent namespace is created by a bind mount.
*-U*, *--user*[**=**__file__]::
- Unshare the user namespace. If _file_ is specified, then a persistent namespace is created by a bind mount.
+Unshare the user namespace. If _file_ is specified, then a persistent namespace is created by a bind mount.
*-C*, *--cgroup*[**=**__file__]::
- Unshare the cgroup namespace. If _file_ is specified, then persistent namespace is created by bind mount.
+Unshare the cgroup namespace. If _file_ is specified, then persistent namespace is created by bind mount.
*-T*, *--time*[**=**__file__]::
- Unshare the time namespace. If _file_ is specified, then a persistent namespace is created by a bind mount. The *--monotonic* and *--boottime* options can be used to specify the corresponding offset in the time namespace.
+Unshare the time namespace. If _file_ is specified, then a persistent namespace is created by a bind mount. The *--monotonic* and *--boottime* options can be used to specify the corresponding offset in the time namespace.
*-f*, *--fork*::
- Fork the specified _program_ as a child process of *unshare* rather than running it directly. This is useful when creating a new PID namespace. Note that when *unshare* is waiting for the child process, then it ignores *SIGINT* and *SIGTERM* and does not forward any signals to the child. It is necessary to send signals to the child process.
+Fork the specified _program_ as a child process of *unshare* rather than running it directly. This is useful when creating a new PID namespace. Note that when *unshare* is waiting for the child process, then it ignores *SIGINT* and *SIGTERM* and does not forward any signals to the child. It is necessary to send signals to the child process.
*--keep-caps*::
- When the *--user* option is given, ensure that capabilities granted in the user namespace are preserved in the child process.
+When the *--user* option is given, ensure that capabilities granted in the user namespace are preserved in the child process.
*--kill-child*[**=**__signame__]::
- When *unshare* terminates, have _signame_ be sent to the forked child process. Combined with *--pid* this allows for an easy and reliable killing of the entire process tree below *unshare*. If not given, _signame_ defaults to *SIGKILL*. This option implies *--fork*.
+When *unshare* terminates, have _signame_ be sent to the forked child process. Combined with *--pid* this allows for an easy and reliable killing of the entire process tree below *unshare*. If not given, _signame_ defaults to *SIGKILL*. This option implies *--fork*.
*--mount-proc*[**=**__mountpoint__]::
- Just before running the program, mount the proc filesystem at _mountpoint_ (default is _/proc_). This is useful when creating a new PID namespace. It also implies creating a new mount namespace since the _/proc_ mount would otherwise mess up existing programs on the system. The new proc filesystem is explicitly mounted as private (with *MS_PRIVATE*|*MS_REC*).
+Just before running the program, mount the proc filesystem at _mountpoint_ (default is _/proc_). This is useful when creating a new PID namespace. It also implies creating a new mount namespace since the _/proc_ mount would otherwise mess up existing programs on the system. The new proc filesystem is explicitly mounted as private (with *MS_PRIVATE*|*MS_REC*).
**--map-user=**__uid|name__::
- Run the program only after the current effective user ID has been mapped to _uid_. If this option is specified multiple times, the last occurrence takes precedence. This option implies *--user*.
+Run the program only after the current effective user ID has been mapped to _uid_. If this option is specified multiple times, the last occurrence takes precedence. This option implies *--user*.
**--map-group=**__gid|name__::
- Run the program only after the current effective group ID has been mapped to _gid_. If this option is specified multiple times, the last occurrence takes precedence. This option implies *--setgroups=deny* and *--user*.
+Run the program only after the current effective group ID has been mapped to _gid_. If this option is specified multiple times, the last occurrence takes precedence. This option implies *--setgroups=deny* and *--user*.
*-r*, *--map-root-user*::
- Run the program only after the current effective user and group IDs have been mapped to the superuser UID and GID in the newly created user namespace. This makes it possible to conveniently gain capabilities needed to manage various aspects of the newly created namespaces (such as configuring interfaces in the network namespace or mounting filesystems in the mount namespace) even when run unprivileged. As a mere convenience feature, it does not support more sophisticated use cases, such as mapping multiple ranges of UIDs and GIDs. This option implies *--setgroups=deny* and *--user*. This option is equivalent to *--map-user=0 --map-group=0*.
+Run the program only after the current effective user and group IDs have been mapped to the superuser UID and GID in the newly created user namespace. This makes it possible to conveniently gain capabilities needed to manage various aspects of the newly created namespaces (such as configuring interfaces in the network namespace or mounting filesystems in the mount namespace) even when run unprivileged. As a mere convenience feature, it does not support more sophisticated use cases, such as mapping multiple ranges of UIDs and GIDs. This option implies *--setgroups=deny* and *--user*. This option is equivalent to *--map-user=0 --map-group=0*.
*-c*, *--map-current-user*::
- Run the program only after the current effective user and group IDs have been mapped to the same UID and GID in the newly created user namespace. This option implies *--setgroups=deny* and *--user*. This option is equivalent to *--map-user=$(id -ru) --map-group=$(id -rg)*.
+Run the program only after the current effective user and group IDs have been mapped to the same UID and GID in the newly created user namespace. This option implies *--setgroups=deny* and *--user*. This option is equivalent to *--map-user=$(id -ru) --map-group=$(id -rg)*.
**--propagation private**|**shared**|**slave**|*unchanged*::
- Recursively set the mount propagation flag in the new mount namespace. The default is to set the propagation to _private_. It is possible to disable this feature with the argument *unchanged*. The option is silently ignored when the mount namespace (*--mount*) is not requested.
+Recursively set the mount propagation flag in the new mount namespace. The default is to set the propagation to _private_. It is possible to disable this feature with the argument *unchanged*. The option is silently ignored when the mount namespace (*--mount*) is not requested.
**--setgroups allow**|*deny*::
- Allow or deny the *setgroups*(2) system call in a user namespace. +
- {nbsp} +
- To be able to call *setgroups*(2), the calling process must at least have *CAP_SETGID*. But since Linux 3.19 a further restriction applies: the kernel gives permission to call *setgroups*(2) only after the GID map (**/proc/**__pid__*/gid_map*) has been set. The GID map is writable by root when *setgroups*(2) is enabled (i.e., *allow*, the default), and the GID map becomes writable by unprivileged processes when *setgroups*(2) is permanently disabled (with *deny*).
+Allow or deny the *setgroups*(2) system call in a user namespace.
++
+To be able to call *setgroups*(2), the calling process must at least have *CAP_SETGID*. But since Linux 3.19 a further restriction applies: the kernel gives permission to call *setgroups*(2) only after the GID map (**/proc/**__pid__*/gid_map*) has been set. The GID map is writable by root when *setgroups*(2) is enabled (i.e., *allow*, the default), and the GID map becomes writable by unprivileged processes when *setgroups*(2) is permanently disabled (with *deny*).
*-R*, **--root=**__dir__::
- run the command with root directory set to _dir_.
+run the command with root directory set to _dir_.
*-w*, **--wd=**__dir__::
- change working directory to _dir_.
+change working directory to _dir_.
*-S*, *--setuid* _uid_::
- Set the user ID which will be used in the entered namespace.
+Set the user ID which will be used in the entered namespace.
*-G*, *--setgid* _gid_::
- Set the group ID which will be used in the entered namespace and drop supplementary groups.
+Set the group ID which will be used in the entered namespace and drop supplementary groups.
*--monotonic* _offset_::
- Set the offset of *CLOCK_MONOTONIC* which will be used in the entered time namespace. This option requires unsharing a time namespace with *--time*.
+Set the offset of *CLOCK_MONOTONIC* which will be used in the entered time namespace. This option requires unsharing a time namespace with *--time*.
*--boottime* _offset_::
- Set the offset of *CLOCK_BOOTTIME* which will be used in the entered time namespace. This option requires unsharing a time namespace with *--time*.
+Set the offset of *CLOCK_BOOTTIME* which will be used in the entered time namespace. This option requires unsharing a time namespace with *--time*.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== NOTES
== AUTHORS
-mailto:dottedmag@dottedmag.net[Mikhail Gusarov] +
+mailto:dottedmag@dottedmag.net[Mikhail Gusarov],
mailto:kzak@redhat.com[Karel Zak]
== SEE ALSO
== OPTIONS
*-f*, *--flags* _list_::
- Print only the specified flags.
+Print only the specified flags.
*-F*, *--noflags*::
- Do not print information about flags.
+Do not print information about flags.
*-I*, *--noident*::
- Do not print watchdog identity information.
+Do not print watchdog identity information.
*-n*, *--noheadings*::
- Do not print a header line for flags table.
+Do not print a header line for flags table.
*-o*, *--output* _list_::
- Define the output columns to use in table of watchdog flags. If no output arrangement is specified, then a default set is used. Use *--help* to get list of all supported columns.
+Define the output columns to use in table of watchdog flags. If no output arrangement is specified, then a default set is used. Use *--help* to get list of all supported columns.
*-O*, *--oneline*::
- Print all wanted information on one line in key="value" output format.
+Print all wanted information on one line in key="value" output format.
*-r*, *--raw*::
- Use the raw output format.
+Use the raw output format.
*-s*, *-settimeout* _seconds_::
- Set the watchdog timeout in seconds.
+Set the watchdog timeout in seconds.
*-T*, *--notimeouts*::
- Do not print watchdog timeouts.
+Do not print watchdog timeouts.
*-x*, *--flags-only*::
- Same as *-I -T*.
+Same as *-I -T*.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== AUTHORS
-mailto:kzak@redhat.com[Karel Zak] +
+mailto:kzak@redhat.com[Karel Zak],
mailto:lennart@poettering.net[Lennart Poettering]
include::../man-common/bugreports.adoc[]
== OPTIONS
*-a*, **--algorithm lzo**|**lz4**|**lz4hc**|**deflate**|*842*::
- Set the compression algorithm to be used for compressing data in the zram device.
+Set the compression algorithm to be used for compressing data in the zram device.
*-f*, *--find*::
- Find the first unused zram device. If a *--size* argument is present, then initialize the device.
+Find the first unused zram device. If a *--size* argument is present, then initialize the device.
*-n*, *--noheadings*::
- Do not print a header line in status output.
+Do not print a header line in status output.
*-o*, *--output* _list_::
- Define the status output columns to be used. If no output arrangement is specified, then a default set is used. Use *--help* to get a list of all supported columns.
+Define the status output columns to be used. If no output arrangement is specified, then a default set is used. Use *--help* to get a list of all supported columns.
*--output-all*::
- Output all available columns.
+Output all available columns.
*--raw*::
- Use the raw format for status output.
+Use the raw format for status output.
*-r*, *--reset*::
- Reset the options of the specified zram device(s). Zram device settings can be changed only after a reset.
+Reset the options of the specified zram device(s). Zram device settings can be changed only after a reset.
*-s*, *--size* _size_::
- Create a zram device of the specified _size_. Zram devices are aligned to memory pages; when the requested _size_ is not a multiple of the page size, it will be rounded up to the next multiple. When not otherwise specified, the unit of the _size_ parameter is bytes. +
- {nbsp} +
- The _size_ argument may be followed by the multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is optional, e.g., "K" has the same meaning as "KiB") or the suffixes KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
+Create a zram device of the specified _size_. Zram devices are aligned to memory pages; when the requested _size_ is not a multiple of the page size, it will be rounded up to the next multiple. When not otherwise specified, the unit of the _size_ parameter is bytes.
++
+The _size_ argument may be followed by the multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is optional, e.g., "K" has the same meaning as "KiB") or the suffixes KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
*-t*, *--streams* _number_::
- Set the maximum number of compression streams that can be used for the device. The default is one stream.
+Set the maximum number of compression streams that can be used for the device. The default is one stream.
*-V*, *--version*::
- Display version information and exit.
+Display version information and exit.
*-h*, *--help*::
- Display help text and exit.
+Display help text and exit.
== EXIT STATUS
== FILES
_/dev/zram[0..N]_::
- zram block devices
+zram block devices
== EXAMPLE
== AUTHORS
-mailto:nefelim4ag@gmail.com[Timofey Titovets] +
+mailto:nefelim4ag@gmail.com[Timofey Titovets],
mailto:kzak@redhat.com[Karel Zak]
== SEE ALSO
projects / thirdparty / util-linux.git / commitdiff
