misc-utils/lsblk.8

   1 .TH LSBLK 8 "February 2013" "util-linux" "System Administration"
   2 .SH NAME
   3 lsblk \- list block devices
   4 .SH SYNOPSIS
   5 .B lsblk
   6 [options]
   7 .RI [ device ...]
   8 .SH DESCRIPTION
   9 .B lsblk
  10 lists information about all available or the specified block devices.  The
  11 .B lsblk
  12 command reads the
  13 .B sysfs
  14 filesystem and
  15 .B udev db
  16 to gather information. If the udev db is not available or lsblk is compiled without udev support than it
  17 tries to read LABELs, UUIDs and filesystem types from the block device. In this case root permissions
  18 are necessary.
  19 .PP
  20 The command prints all block devices (except RAM disks) in a tree-like format
  21 by default.  Use
  22 .B "lsblk \-\-help"
  23 to get a list of all available columns.
  24 .PP
  25 The default output, as well as the default output from options like
  26 .B \-\-fs
  27 and
  28 .BR \-\-topology ,
  29 is subject to change.  So whenever possible, you should avoid using default
  30 outputs in your scripts.  Always explicitly define expected columns by using
  31 .B \-\-output
  32 .I columns-list
  33 and
  34 .B \-\-list
  35 in environments where a stable output is required.
  36 .PP
  37 Note that
  38 .B lsblk
  39 might be executed in time when
  40 .B udev
  41 does not have all information about recently added or modified devices yet. In this
  42 case it is recommended to use
  43 .B "udevadm settle"
  44 before lsblk to synchronize with udev.
  45 .SH OPTIONS
  46 .TP
  47 .BR \-a , " \-\-all"
  48 Also list empty devices and RAM disk devices.
  49 .TP
  50 .BR \-b , " \-\-bytes"
  51 Print the SIZE column in bytes rather than in a human-readable format.
  52 .TP
  53 .BR \-D , " \-\-discard"
  54 Print information about the discarding capabilities (TRIM, UNMAP) for each device.
  55 .TP
  56 .BR \-d , " \-\-nodeps"
  57 Do not print holder devices or slaves.  For example, \fBlsblk \-\-nodeps /dev/sda\fR prints
  58 information about the sda device only.
  59 .TP
  60 .BR \-E , " \-\-dedup " \fIcolumn\fP
  61 Use \fIcolumn\fP as a de-duplication key to de-duplicate output tree. If the
  62 key is not available for the device, or the device is a partition and parental
  63 whole-disk device provides the same key than the device is always printed.
  64
  65 The usual use case is to de-duplicate output on system multi-path devices, for
  66 example by \fB\-E WWN\fR.
  67 .TP
  68 .BR \-e , " \-\-exclude " \fIlist\fP
  69 Exclude the devices specified by the comma-separated \fIlist\fR of major device numbers.
  70 Note that RAM disks (major=1) are excluded by default if \fB\-\-all\fR is not specified.
  71 The filter is applied to the top-level devices only. This may be confusing for
  72 \fB\-\-list\fR output format where hierarchy of the devices is not obvious.
  73 .TP
  74 .BR \-f , " \-\-fs"
  75 Output info about filesystems.  This option is equivalent to
  76 .BR \-o\ NAME,FSTYPE,LABEL,UUID,FSAVAIL,FSUSE%,MOUNTPOINT .
  77 The authoritative information about filesystems and raids is provided by the
  78 .BR blkid (8)
  79 command.
  80 .TP
  81 .BR \-h , " \-\-help"
  82 Display help text and exit.
  83 .TP
  84 .BR \-I , " \-\-include " \fIlist\fP
  85 Include devices specified by the comma-separated \fIlist\fR of major device numbers.
  86 The filter is applied to the top-level devices only. This may be confusing for
  87 \fB\-\-list\fR output format where hierarchy of the devices is not obvious.
  88 .TP
  89 .BR \-i , " \-\-ascii"
  90 Use ASCII characters for tree formatting.
  91 .TP
  92 .BR \-J , " \-\-json"
  93 Use JSON output format.  It's strongly recommended to use \fB\-\-output\fR and
  94 also \fB\-\-tree\fR if necessary.
  95 .TP
  96 .BR \-l , " \-\-list"
  97 Produce output in the form of a list. The output does not provide information
  98 about relationships between devices and since version 2.34 every device is
  99 printed only once if \fB\-\-pairs\fR or \fB\-\-raw\fR not specified (the
 100 parsable outputs are maintained in backwardly compatible way).
 101 .TP
 102 .BR \-M , " \-\-merge"
 103 Group parents of sub-trees to provide more readable output for RAIDs and
 104 Multi-path devices. The tree-like output is required.
 105 .TP
 106 .BR \-m , " \-\-perms"
 107 Output info about device owner, group and mode.  This option is equivalent to
 108 .BR \-o\ NAME,SIZE,OWNER,GROUP,MODE .
 109 .TP
 110 .BR \-n , " \-\-noheadings"
 111 Do not print a header line.
 112 .TP
 113 .BR \-o , " \-\-output " \fIlist\fP
 114 Specify which output columns to print.  Use
 115 .B \-\-help
 116 to get a list of all supported columns.  The columns may affect tree-like output.
 117 The default is to use tree for the column 'NAME' (see also \fB\-\-tree\fR).
 118
 119 The default list of columns may be extended if \fIlist\fP is
 120 specified in the format \fI+list\fP (e.g., \fBlsblk \-o +UUID\fP).
 121 .TP
 122 .BR \-O , " \-\-output\-all"
 123 Output all available columns.
 124 .TP
 125 .BR \-P , " \-\-pairs"
 126 Produce output in the form of key="value" pairs.  The output lines are still ordered by
 127 dependencies.  All potentially unsafe characters are hex-escaped (\\x<code>).
 128 .TP
 129 .BR \-p , " \-\-paths"
 130 Print full device paths.
 131 .TP
 132 .BR \-r , " \-\-raw"
 133 Produce output in raw format.  The output lines are still ordered by
 134 dependencies.  All potentially unsafe characters are hex-escaped
 135 (\\x<code>) in the NAME, KNAME, LABEL, PARTLABEL and MOUNTPOINT columns.
 136 .TP
 137 .BR \-S , " \-\-scsi"
 138 Output info about SCSI devices only.  All partitions, slaves and holder devices are ignored.
 139 .TP
 140 .BR \-s , " \-\-inverse"
 141 Print dependencies in inverse order. If the \fB\-\-list\fR output is requested then
 142 the lines are still ordered by dependencies.
 143 .TP
 144 .BR \-T , " \-\-tree" [ =\fIcolumn ]
 145 Force tree-like output format.  If \fIcolumn\fP is specified, then a tree is printed in the column.
 146 The default is NAME column.
 147 .TP
 148 .BR \-t , " \-\-topology"
 149 Output info about block-device topology.
 150 This option is equivalent to
 151 .BR \-o\ NAME,ALIGNMENT,MIN-IO,OPT-IO,PHY-SEC,LOG-SEC,ROTA,SCHED,RQ-SIZE,RA,WSAME .
 152 .TP
 153 .BR \-V , " \-\-version"
 154 Display version information and exit.
 155 .TP
 156 .BR \-x , " \-\-sort " \fIcolumn\fP
 157 Sort output lines by \fIcolumn\fP. This option enables \fB\-\-list\fR output format by default.
 158 It is possible to use the option \fI\-\-tree\fP to force tree-like output and
 159 than the tree branches are sorted by the \fIcolumn\fP.
 160 .TP
 161 .BR \-z , " \-\-zoned"
 162 Print the zone model for each device.
 163 .TP
 164 .BR " \-\-sysroot " \fIdirectory\fP
 165 Gather data for a Linux instance other than the instance from which the lsblk
 166 command is issued.  The specified directory is the system root of the Linux
 167 instance to be inspected.  The real device nodes in the target directory can
 168 be replaced by text files with udev attributes.
 169
 170 .SH EXIT STATUS
 171 .IP 0
 172 success
 173 .IP 1
 174 failure
 175 .IP 32
 176 none of specified devices found
 177 .IP 64
 178 some specified devices found, some not found
 179
 180 .SH ENVIRONMENT
 181 .IP LSBLK_DEBUG=all
 182 enables lsblk debug output.
 183 .IP LIBBLKID_DEBUG=all
 184 enables libblkid debug output.
 185 .IP LIBMOUNT_DEBUG=all
 186 enables libmount debug output.
 187 .IP LIBSMARTCOLS_DEBUG=all
 188 enables libsmartcols debug output.
 189 .IP LIBSMARTCOLS_DEBUG_PADDING=on
 190 use visible padding characters. Requires enabled LIBSMARTCOLS_DEBUG.
 191 .SH NOTES
 192 For partitions, some information (e.g., queue attributes) is inherited from the
 193 parent device.
 194 .PP
 195 The
 196 .B lsblk
 197 command needs to be able to look up each block device by major:minor numbers,
 198 which is done by using
 199 .IR /sys/dev/block .
 200 This sysfs block directory appeared in kernel 2.6.27 (October 2008).
 201 In case of problems with a new enough kernel, check that CONFIG_SYSFS
 202 was enabled at the time of the kernel build.
 203
 204 .SH AUTHORS
 205 .nf
 206 Milan Broz <mbroz@redhat.com>
 207 Karel Zak <kzak@redhat.com>
 208 .fi
 209 .SH SEE ALSO
 210 .BR ls (1),
 211 .BR blkid (8),
 212 .BR findmnt (8)
 213 .SH AVAILABILITY
 214 The lsblk command is part of the util-linux package and is available from
 215 https://www.kernel.org/pub/linux/utils/util-linux/.