lsblk Command Examples and Usages

The Lsblk command is used to display details about block devices and these block devices (Except ram disk) are basically those files that represent devices connected to the computer. It queries /sys virtual file system and udev db to obtain information that it displays. And it basically displays output in a tree-like structure. The lsblk command examples are helps you learn lsblk command faster. Lear more Linux Command Line.

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 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.

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, UN‐MAP) 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,LABEL,UUID,FSAVAIL,FSUSE%,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 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 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,LOGSEC,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.

-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. Requires enabled LIBSMARTCOLS_DEBUG.

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.

lsblk Command Examples

Creating swap partition using fdisk command.

SEE ALSO

ls(1), blkid(8), findmnt(8)