How to format disks and partitions in Linux

Disks and partitions need to be formatted before it can be mounted and used. Linux by default supports formatting disks and partitions to several filesystem types, which each would come with their pros and cons. Some of the popular supported filesystem types are ext4, Btrfs, and exFAT.

While various graphical tools exist for formatting disks and partitions, most Linux distributions come with the command-line tool mkfs installed by default. This tool is often the foundation for many graphical formatting tools.

1. Open the terminal.
2. Display the available disks and partitions on your system.

   $ lsblk
   NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
   loop0    7:0    0  55.4M  1 loop /snap/core18/19
   loop1    7:1    0  55.4M  1 loop /snap/core18/19
   loop2    7:2    0    51M  1 loop /snap/snap-stor
   loop3    7:3    0   219M  1 loop /snap/gnome-3-3
   loop4    7:4    0 217.9M  1 loop /snap/gnome-3-3
   loop5    7:5    0  31.1M  1 loop /snap/snapd/104
   loop6    7:6    0  62.1M  1 loop /snap/gtk-commo
   loop7    7:7    0  64.8M  1 loop /snap/gtk-commo
   loop8    7:8    0    51M  1 loop /snap/snap-stor
   loop9    7:9    0  31.1M  1 loop /snap/snapd/107
   sda      8:0    0    20G  0 disk 
   ├─sda1   8:1    0     1M  0 part 
   ├─sda2   8:2    0   513M  0 part /boot/efi
   └─sda3   8:3    0  19.5G  0 part /
   sdb      8:16   0    20G  0 disk 
   └─sdb1   8:17   0    20G  0 part 
   sr0     11:0    1  1024M  0 rom

3. Ensure the disk or partition you want to format is not mounted or in use.

   $ sudo umount /dev/sdb1
   [sudo] password for user: 
   umount: /dev/sdb1: not mounted.

4. Verify the supported filesystems for the mkfs command.

   $ sudo mkfs.
   mkfs.bfs     mkfs.ext4    mkfs.ntfs
   mkfs.cramfs  mkfs.fat     mkfs.vfat
   mkfs.ext2    mkfs.minix   
   mkfs.ext3    mkfs.msdos

   Type mkfs. and press <TAB> twice for the terminal to show possible autompleted commands.

   Install necessary package if your desired filestem is not listed or supported.

5. Format the disk or partition using your desired filesystem type.

   $ sudo mkfs.ext4 /dev/sdb1
   mke2fs 1.45.6 (20-Mar-2020)
   Creating filesystem with 5242624 4k blocks and 1310720 inodes
   Filesystem UUID: ccab0f8d-3b5b-4189-9da3-23c49159c318
   Superblock backups stored on blocks: 
   	32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
   	4096000
   
   Allocating group tables: done                            
   Writing inode tables: done                            
   Creating journal (32768 blocks): done
   Writing superblocks and filesystem accounting information: done
6. Confirm the current filesystem type to ensure the disk or partition has been formatted successfully.

   $ blkid /dev/sdb1 
   /dev/sdb1: UUID="ccab0f8d-3b5b-4189-9da3-23c49159c318" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="c088a647-01"

7. Mount the disk or partition as needed.

   Related: How to mount disks and partitions in Linux