lsblk(8) - phpMan

LSBLK(8) System Administration LSBLK(8)

NAME
lsblk - list block devices

SYNOPSIS
lsblk [options] [device...]

DESCRIPTION
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.

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.

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.

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.

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.

OPTIONS
-a, --all
Also list empty devices and RAM disk devices.

-b, --bytes
Print the SIZE column in bytes rather than in a human-readable format.

-D, --discard
Print information about the discarding capabilities (TRIM, UNMAP) for each device.

-d, --nodeps
Do not print holder devices or slaves. For example, lsblk --nodeps /dev/sda prints
information about the sda device only.

-E, --dedup column
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.

The usual use case is to de-duplicate output on system multi-path devices, for example
by -E WWN.

-e, --exclude list
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.

-f, --fs
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.

-h, --help
Display help text and exit.

-I, --include list
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.

-i, --ascii
Use ASCII characters for tree formatting.

-J, --json
Use JSON output format. It's strongly recommended to use --output and also --tree if
necessary.

-l, --list
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).

-M, --merge
Group parents of sub-trees to provide more readable output for RAIDs and Multi-path
devices. The tree-like output is required.

-m, --perms
Output info about device owner, group and mode. This option is equivalent to -o
NAME,SIZE,OWNER,GROUP,MODE.

-n, --noheadings
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 columns may affect tree-like output. The default is to use tree for the
column 'NAME' (see also --tree).

The default list of columns may be extended if list is specified in the format +list
(e.g., lsblk -o +UUID).

-O, --output-all
Output all available columns.

-P, --pairs
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>).

-p, --paths
Print full device paths.

-r, --raw
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.

-S, --scsi
Output info about SCSI devices only. All partitions, slaves and holder devices are
ignored.

-s, --inverse
Print dependencies in inverse order. If the --list output is requested then the lines
are still ordered by dependencies.

-T, --tree[=column]
Force tree-like output format. If column is specified, then a tree is printed in the
column. The default is NAME column.

-t, --topology
Output info about block-device topology. This option is equivalent to

-o NAME,ALIGNMENT,MIN-IO,OPT-IO,PHY-SEC,LOG-SEC,ROTA,SCHED,RQ-SIZE,RA,WSAME.

-V, --version
Display version information and exit.

-w, --width number
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.

-x, --sort column
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.

-z, --zoned
Print the zone model for each device.

--sysroot directory
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.

EXIT STATUS
0
success

1
failure

32
none of specified devices found

64
some specified devices found, some not found

ENVIRONMENT
LSBLK_DEBUG=all
enables lsblk debug output.

LIBBLKID_DEBUG=all
enables libblkid debug output.

LIBMOUNT_DEBUG=all
enables libmount debug output.

LIBSMARTCOLS_DEBUG=all
enables libsmartcols debug output.

LIBSMARTCOLS_DEBUG_PADDING=on
use visible padding characters.

NOTES
For partitions, some information (e.g., queue attributes) is inherited from the parent
device.

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.

AUTHORS
Milan Broz <mbroz AT redhat.com>, Karel Zak <kzak AT redhat.com>