misc-utils/lsblk.8.adoc

   1 //po4a: entry man manual
   2 = lsblk(8)
   3 :doctype: manpage
   4 :man manual: System Administration
   5 :man source: util-linux {release-version}
   6 :page-layout: base
   7 :command: lsblk
   8
   9 == NAME
  10
  11 lsblk - list block devices
  12
  13 == SYNOPSIS
  14
  15 *lsblk* [options] [_device_...]
  16
  17 == DESCRIPTION
  18
  19 *lsblk* lists information about all available or the specified block devices. The *lsblk* command reads the *sysfs* filesystem and *udev db* to gather information. If the udev db is not available or *lsblk* is compiled without udev support, then it tries to read LABELs, UUIDs and filesystem types from the block device. In this case root permissions are necessary.
  20
  21 The command prints all block devices (except RAM disks) in a tree-like format by default. Use *lsblk --help* to get a list of all available columns.
  22
  23 The default output, as well as the default output from options like *--fs* and *--topology*, is subject to change. So whenever possible, you should avoid using default outputs in your scripts. Always explicitly define expected columns by using *--output* _columns-list_ and *--list* in environments where a stable output is required.
  24
  25 Note that *lsblk* might be executed in time when *udev* does not have all information about recently added or modified devices yet. In this case it is recommended to use *udevadm settle* before *lsblk* to synchronize with udev.
  26
  27 The relationship between block devices and filesystems is not always one-to-one. The filesystem may use more block devices, or the same filesystem may be accessible by more paths. This is the reason why *lsblk* provides MOUNTPOINT and MOUNTPOINTS (pl.) columns. The column MOUNTPOINT displays only one mount point (usually the last mounted instance of the filesystem), and the column MOUNTPOINTS displays by multi-line cell all mount points associated with the device.
  28
  29 == OPTIONS
  30
  31 *-A*, *--noempty*::
  32 Don't print empty devices.
  33
  34 *-a*, *--all*::
  35 Disable all built-in filters and list all empty devices and RAM disk devices too.
  36
  37 *-b*, *--bytes*::
  38 include::man-common/in-bytes.adoc[]
  39
  40 *-D*, *--discard*::
  41 Print information about the discarding capabilities (TRIM, UNMAP) for each device.
  42
  43 *-d*, *--nodeps*::
  44 Do not print holder devices or slaves. For example, *lsblk --nodeps /dev/sda* prints information about the sda device only.
  45
  46 *-E*, *--dedup* _column_::
  47 Use _column_ as a de-duplication key to de-duplicate output tree. If the key is not available for the device, or the device is a partition and parental whole-disk device provides the same key than the device is always printed.
  48 +
  49 The usual use case is to de-duplicate output on system multi-path devices, for example by *-E WWN*.
  50
  51 *-e*, *--exclude* _list_::
  52 Exclude the devices specified by the comma-separated _list_ of major device numbers. Note that RAM disks (major=1) are excluded by default if *--all* is not specified. The filter is applied to the top-level devices only. This may be confusing for *--list* output format where hierarchy of the devices is not obvious.
  53
  54 *-f*, *--fs*::
  55 Output info about filesystems. This option is equivalent to *-o NAME,FSTYPE,FSVER,LABEL,UUID,FSAVAIL,FSUSE%,MOUNTPOINTS*. The authoritative information about filesystems and raids is provided by the *blkid*(8) command.
  56
  57 *-I*, *--include* _list_::
  58 Include devices specified by the comma-separated _list_ of major device numbers. The filter is applied to the top-level devices only. This may be confusing for *--list* output format where hierarchy of the devices is not obvious.
  59
  60 *-i*, *--ascii*::
  61 Use ASCII characters for tree formatting.
  62
  63 *-J*, *--json*::
  64 Use JSON output format. It's strongly recommended to use *--output* and also *--tree* if necessary.
  65
  66 *-l*, *--list*::
  67 Produce output in the form of a list. The output does not provide information about relationships between devices and since version 2.34 every device is printed only once if *--pairs* or *--raw* not specified (the parsable outputs are maintained in backwardly compatible way).
  68
  69 *-M*, *--merge*::
  70 Group parents of sub-trees to provide more readable output for RAIDs and Multi-path devices. The tree-like output is required.
  71
  72 *-m*, *--perms*::
  73 Output info about device owner, group and mode. This option is equivalent to *-o NAME,SIZE,OWNER,GROUP,MODE*.
  74
  75 *-n*, *--noheadings*::
  76 Do not print a header line.
  77
  78 *-o*, *--output* _list_::
  79 Specify which output columns to print. Use *--help* to get a list of all supported columns. The columns may affect tree-like output. The default is to use tree for the column 'NAME' (see also *--tree*).
  80 +
  81 The default list of columns may be extended if _list_ is specified in the format _+list_ (e.g., *lsblk -o +UUID*).
  82
  83 *-O*, *--output-all*::
  84 Output all available columns.
  85
  86 *-P*, *--pairs*::
  87 Produce output in the form of key="value" pairs. The output lines are still ordered by dependencies. All potentially unsafe value characters are hex-escaped (\x<code>). See also option *--shell*.
  88
  89 *-p*, *--paths*::
  90 Print full device paths.
  91
  92 *-r*, *--raw*::
  93 Produce output in raw format. The output lines are still ordered by dependencies. All potentially unsafe characters are hex-escaped (\x<code>) in the NAME, KNAME, LABEL, PARTLABEL and MOUNTPOINT columns.
  94
  95 *-S*, *--scsi*::
  96 Output info about SCSI devices only. All partitions, slaves and holder devices are ignored.
  97
  98 *-s*, *--inverse*::
  99 Print dependencies in inverse order. If the *--list* output is requested then the lines are still ordered by dependencies.
 100
 101 *-T*, *--tree*[**=**__column__]::
 102 Force tree-like output format. If _column_ is specified, then a tree is printed in the column. The default is NAME column.
 103
 104 *-t*, *--topology*::
 105 Output info about block-device topology. This option is equivalent to
 106 +
 107 *-o NAME,ALIGNMENT,MIN-IO,OPT-IO,PHY-SEC,LOG-SEC,ROTA,SCHED,RQ-SIZE,RA,WSAME*.
 108
 109 include::man-common/help-version.adoc[]
 110
 111 *-w*, *--width* _number_::
 112 Specifies output width as a number of characters. The default is the number of the terminal columns, and if not executed on a terminal, then output width is not restricted at all by default. This option also forces *lsblk* to assume that terminal control characters and unsafe characters are not allowed. The expected use-case is for example when *lsblk* is used by the *watch*(1) command.
 113
 114 *-x*, *--sort* _column_::
 115 Sort output lines by _column_. This option enables *--list* output format by default. It is possible to use the option *--tree* to force tree-like output and than the tree branches are sorted by the _column_.
 116
 117 *-y*, *--shell*::
 118 The column name will be modified to contain only characters allowed for shell variable identifiers, for example, MIN_IO and FSUSE_PCT instead of MIN-IO and FSUSE%. This is usable, for example, with *--pairs*. Note that this feature has been automatically enabled for *--pairs* in version 2.37, but due to compatibility issues, now it's necessary to request this behavior by *--shell*.
 119
 120 *-z*, *--zoned*::
 121 Print the zone related information for each device.
 122
 123 *--sysroot* _directory_::
 124 Gather data for a Linux instance other than the instance from which the *lsblk* command is issued. The specified directory is the system root of the Linux instance to be inspected. The real device nodes in the target directory can be replaced by text files with udev attributes.
 125
 126 == EXIT STATUS
 127
 128 0::
 129 success
 130
 131 1::
 132 failure
 133
 134 32::
 135 none of specified devices found
 136
 137 64::
 138 some specified devices found, some not found
 139
 140 == ENVIRONMENT
 141
 142 *LSBLK_DEBUG*=all::
 143 enables *lsblk* debug output.
 144
 145 *LIBBLKID_DEBUG*=all::
 146 enables *libblkid* debug output.
 147
 148 *LIBMOUNT_DEBUG*=all::
 149 enables *libmount* debug output.
 150
 151 *LIBSMARTCOLS_DEBUG*=all::
 152 enables *libsmartcols* debug output.
 153
 154 *LIBSMARTCOLS_DEBUG_PADDING*=on::
 155 use visible padding characters.
 156
 157 == NOTES
 158
 159 For partitions, some information (e.g., queue attributes) is inherited from the parent device.
 160
 161 The *lsblk* command needs to be able to look up each block device by major:minor numbers, which is done by using _/sys/dev/block_. This sysfs block directory appeared in kernel 2.6.27 (October 2008). In case of problems with a new enough kernel, check that *CONFIG_SYSFS* was enabled at the time of the kernel build.
 162
 163 == AUTHORS
 164
 165 mailto:mbroz@redhat.com[Milan Broz],
 166 mailto:kzak@redhat.com[Karel Zak]
 167
 168 == SEE ALSO
 169
 170 *ls*(1),
 171 *blkid*(8),
 172 *findmnt*(8)
 173
 174 include::man-common/bugreports.adoc[]
 175
 176 include::man-common/footer.adoc[]
 177
 178 ifdef::translation[]
 179 include::man-common/translation.adoc[]
 180 endif::[]