Photo by Iker Urteaga on unsplash.com
This post was originally published on my personal blog mariadcampbell.com.
Table of Contents
- lsblk introduction
- What is the lsblk command and what does it do?
- Installing util-linux if your distro does not have it by default
- lsblk syntax
- Running the lsblk command
- Footnotes
- Related Resources
lsblk introduction
The lsblk
command comes as part of the util-linux
package, which is a
package
comprised of essential utilities
for Linux systems
. It provides
a wide range of functionality
including tools
for managing files
, disks
,
and system resources
. util-linux
comes installed with Linux Mint, for
example. According to the Linux Mint community,
(
util-linux
) contains a number of important utilities, most of which are
oriented towards maintenance of your system. Some of the more important
utilities included in this package allow you to view kernel messages, create
new filesystems, viewblock device information
, interface with real time
clock, etc.
What is the lsblk command and what does it do?
The lsblk
command stands for list block devices
, and it provides detailed
information about block devices
such as hard drives
, solid state drives
,
and other storage related devices
that are connected
to the computer
. It
queries the /sys virtual filesystem and
udev db
[^1] to obtain
the information
that it displays
.
Installing util-linux if your distro does not have it by default
If by any chance you are not using Linux Mint
, or Ubuntu
or an
Ubuntu derivate
for example, and your Linux
distro does not contain the
util-linux
package, you can install
it:
# Debian/Ubuntu
sudo apt-get install util-linux
# in Linux Mint, I have installed my packages doing sudo apt install packagename. But util-linus is already installed in Linux Mint anyway.
lsblk syntax
The syntax
for the lsblk
command is the following
:
lsblk [options] [device]
[options]
refers to the flags
available to the lsblk
command. [device]
refers to the specific
block devices that we want
to list
. If no device
is specified
, lsblk
will list
all block devices
.
Running the lsblk command
If I run lsblk
in Terminal
, it returns
the following
:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 50G 0 disk
├─sda1 8:1 0 1M 0 part
├─sda2 8:2 0 513M 0 part /boot/efi
└─sda3 8:3 0 49.5G 0 part /
sr0 11:0 1 50.4M 0 rom /media/maria/VBox_GAs_7.0.18
If I want
to get all block devices
including empty ones
, I would run
the
following
:
lsblk -a
Which
for me returns
:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
loop0 7:0 0 0B 0 loop
loop1 7:1 0 0B 0 loop
loop2 7:2 0 0B 0 loop
loop3 7:3 0 0B 0 loop
loop4 7:4 0 0B 0 loop
loop5 7:5 0 0B 0 loop
loop6 7:6 0 0B 0 loop
loop7 7:7 0 0B 0 loop
sda 8:0 0 50G 0 disk
├─sda1 8:1 0 1M 0 part
├─sda2 8:2 0 513M 0 part /boot/efi
└─sda3 8:3 0 49.5G 0 part /
sr0 11:0 1 50.4M 0 rom /media/maria/VBox_GAs_7.0.18
If I want
to print out
the information
in list format
, I would run
the
following
:
lsblk -l
Which
for me returns
:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 50G 0 disk
sda1 8:1 0 1M 0 part
sda2 8:2 0 513M 0 part /boot/efi
sda3 8:3 0 49.5G 0 part /
sr0 11:0 1 50.4M 0 rom /media/maria/VBox_GAs_7.0.18
Now devices
are listed
without showing which ones
are related
to
each other
like with
the lsblk
command.
If I run
the following command
in Terminal
:
lsblk -p
For me, it returns
the following
:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
/dev/sda 8:0 0 50G 0 disk
├─/dev/sda1 8:1 0 1M 0 part
├─/dev/sda2 8:2 0 513M 0 part /boot/efi
└─/dev/sda3 8:3 0 49.5G 0 part /
/dev/sr0 11:0 1 50.4M 0 rom /media/maria/VBox_GAs_7.0.18
The -p
flag produces output
in key value pairs
. The big difference
here
is the absolute path
to the device
as well as the relationships
between
related devices
is also displayed
. To learn more
about lsblk
, run
man lsblk
in Terminal
.
Footnotes
[^1]: udev (db) or
user /dev
is systemd's device manager for the Linux kernel. It manages device
nodes in /dev and handles all user space actions when adding or removing
devices.
According to man udev
, udev supplies the system software with device events,
manages permissions of device nodes and may create additional symlinks in the
/dev/ directory, or renames network interfaces. The kernel usually just assigns
unpredictable device names based on the order of discovery. Meaningful symlinks
or network device names provide a way to reliably identify devices based on
their properties or current configuration.
The udev daemon,
systemd-udevd.service(8),
receives device uevents directly from the kernel whenever a device is added or
removed from the system, or it changes its state. When udev receives a device
event, it matches its configured set of rules against various device attributes
to identify the device. Rules that match may provide additional device
information to be stored in the udev database or to be used to create meaningful
symlink names.
All device information udev processes is stored in the udev database and sent
out to possible event subscribers. Access to all stored data and the event
sources is provided by the library libudev.
Related Resources
- The Linux Filesystem Hierarchy: mariadcampbell.com
- How to List All Block Devices in Linux | lsblk Command: Geeks for Geeks
Top comments (0)