lsblk Command: Tutorial & Examples

List block devices

The lsblk command in Linux displays a list of all block devices, such as hard drives and their partitions, connected to the machine. It extracts its information directly from the Linux Kernel. Unlike similar commands like fdisk or ls, lsblk provides a tree-like hierarchical structure view of the devices, which is much easier to understand.

Understanding lsblk is crucial for managing storage devices and partitions. It can be used to identify devices and their partitions, check disk space, and diagnose disk related issues.

How lsblk Works

The lsblk command gathers information from the sysfs filesystem under /sys, specifically sysfs/block. It lists all block devices and their associated partitions in a tree-like structure, with the device at the top and its partitions as branches.

Solving Issues with lsblk

lsblk can be helpful in several situations. For example, if you're experiencing a disk space issue, you can use lsblk to quickly check the sizes of your disks and their partitions.

It's also handy if you're unsure which device corresponds to a particular disk or partition. The detailed output of lsblk includes the mount points of partitions, which can help you identify the correct device to work with.

Examples of Using lsblk

Here are a few examples of how to use lsblk:

To list all block devices and partitions in a tree-like structure:

lsblk

Typical output would look like this:

NAME   MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda      8:0    0  10G  0 disk 
├─sda1   8:1    0   1G  0 part /boot
└─sda2   8:2    0   9G  0 part 
  ├─vg_root-lv_root
  │        253:0    0 6.5G  0 lvm  /
  └─vg_root-lv_swap
           253:1    0 2.5G  0 lvm  [SWAP]

To list block devices along with their size and file system type:

lsblk -fs

The output would include additional information:

NAME            FSTYPE LABEL UUID                                 MOUNTPOINT
sda                                                                  
├─sda1         ext4   /boot 
└─sda2         LVM2_member                                           
  ├─vg_root-lv_root
  │           ext4       /                                  
  └─vg_root-lv_swap
             swap       [SWAP]

Conclusion

The lsblk command is a powerful tool for managing and diagnosing issues with your storage devices. Its straightforward output makes it easy to understand the layout of your disks and partitions, and its various options allow you to customize the information displayed.