How to format and/or partition disks in Linux
Just a quick guide to format and partition hard drives in Linux command line that I wrote for myself a long time ago, and recently had to reference again.
Be aware that using these instructions to format a disk or delete partitions will lead to the loss of any data contained therein.
Formatting a disk
Let’s assume you have two disks on your Linux machine and you want to format a specific one. First list your disks with df -h and you should get output like this:
Filesystem Size Used Avail Use% Mounted on
tmpfs 385M 1.3M 383M 1% /run
/dev/sda2 458G 7.3G 427G 2% /
/dev/sdb 687G 538G 114G 83% /mnt/data
tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 385M 4.0K 385M 1% /run/user/1000
We want to format /dev/sdb, but first it needs to be unmounted with sudo umount /dev/sdb, then you would do the following, depending on filesystem you want to use:
sudo mkfs.ext4 /dev/sdb # ext4 filesystem
sudo mkfs.ntfs /dev/sdb # ntfs filesystem
sudo mkfs.vfat /dev/sdb # vfat filesystem
Managing partitions
To manage partitions on a disk, I like to use fdisk since it’s dialog-based and easy to use. Let’s assume /dev/sdb has two partitions — sdb1 and sdb2 — but you want to delete one. Use this command to enter the fdisk dialog:
sudo fdisk /dev/sdb
Command (m for help):
Quick list of some important commands:
mwill list all available commandsdwill prompt you to choose an existing partition to delete (type a number to delete that partition)nwill prompt you to add a new partition and choose the partition type (pfor primary orefor extended)qwill quit without saving changeswwill write to disk and reboot the system
In our case we want to delete the second partition, so at the prompt we’d use d and then 2 to delete that second partition. If we wanted to, we could then delete the first partition (d and 1) then create a new partition to take up the whole disk with n, choosing the defaults for first and last sector.
You’d then use mkfs as above to format the partition with a filesystem, if one is not already present. Alternately, you could delete all partitions and not add any, then use fdisk to format the entire disk. This is actually my preferred method since I have little need for partitions in my home server, and it’s really only necessary if you want to use multiple filesystems in one disk, or if you’re using the disk for swap space.