lsblk

The lsblk (list block devices) command gathers information about all available or the specified block devices. It reads the sysfs filesystem and udev db to gather information. It is incredibly useful for getting a clear, tree-like overview of your hard drives, partitions, and where they are mounted.

Basic Syntax

lsblk [OPTIONS] [DEVICE]

Common Flags/Options

Option	Description
-f, --fs	Output info about filesystems (UUID, labels, FSTYPE). Extremely useful before mounting.
-a, --all	List empty devices as well (e.g., empty CD-ROM drives or unformatted loops).
-m, --perms	Output information about device owner, group, and mode.
-p, --paths	Print full device paths (e.g., /dev/sda instead of just sda).
-o, --output LIST	Specify which output columns to print.

Real-world Examples

1. View a tree of all block devices

This is the standard usage. It shows disks (e.g., sda), their partitions (e.g., sda1, sda2), their sizes, types, and mount points.

lsblk

Output Example:

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda      8:0    0   50G  0 disk 
├─sda1   8:1    0   49G  0 part /
└─sda2   8:2    0    1G  0 part [SWAP]
sdb      8:16   0  100G  0 disk 

2. View filesystem types and UUIDs

When configuring /etc/fstab for permanent mounts, you need the partition UUID and filesystem type.

lsblk -f

Output Example:

NAME   FSTYPE LABEL UUID                                 MOUNTPOINT
sda                                                      
├─sda1 ext4         5f8b9b4a-1b4a-4b5f-a3d1-8b9b4a1b4a4b /
└─sda2 swap         2c3d4e5f-6a7b-8c9d-0e1f-2a3b4c5d6e7f [SWAP]

3. Print full device paths

If you are writing a script and need the exact absolute path to the devices:

lsblk -p