How to format disk and partition in Linux

Disks and partitions need to be formatted before it could be mounted and used. They could be formatted to any supported filesystems which would come with their own pros and cons. Some of the popular filesystem types are ext4, Btrfs, NTFS, and exFAT

There are many graphical tools to help with formatting disks and partitions in Linux. The one that's installed by default in most Linux distributions is mkfs which is a command-line tool and is probably the backend to all the graphical tools.

1. Launch terminal.
2. List available disks and partitions in 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. Make sure disk or partition that you want to format is not already mounted or is in use.

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

4. Check supported filesystem for 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 disk or partition using your preferred 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. Check current filesystem type to ensure disk or partition is successfully formatted.

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

7. Mount disk or partition as necessary.

   Related: How to mount disk and partition in Linux