Linux man pages

Section (8) lsblk

Linux manual pages	Section 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 than 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 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.

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.

−z, −−zoned

Print the zone model 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, −−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 no specified. The filter is applied to the top-level devices only. This maybe 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,LABEL,UUID,MOUNTPOINT. 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 maybe 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.

−l, −−list

Produce output in the form of a list.

−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 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. All potentially unsafe characters are hex-escaped (x<code>).

−p, −−paths

Print full device paths.

−r, −−raw

Produce output in raw format. 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, −−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.

−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.

−−sysrootdirectory

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. This option is designed for the testing purpose.

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.

RETURN CODES

0: success
1: failure
32: none of specified devices found
64: some specified devices found, some not found

AUTHORS

Milan Broz <[email protected]>
Karel Zak <[email protected]>

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. Requires enabled LIBSMARTCOLS_DEBUG.

AVAILABILITY

The lsblk command is part of the util-linux package and is available from https://www.kernel.org/pub/linux/utils/util-linux/.