The mkfs command build a file system on a block device:

# mkfs [options] device

mkfs is a front end for builder utilities in /sbin such as mkfs.ext4. You can use either the mkfs command with the -t fstype option or the builder utility to specify the type of file system to build. For example, the following commands are equivalent ways of creating an ext4 file system with the label Projects on the device /dev/sdb1:

# mkfs -t ext4 -L Projects /dev/sdb1
# mkfs.ext4 -L Projects /dev/sdb1

If you do not specify the file system type to makefs , it creates an ext2 file system.

To display the type of a file system, use the blkid command:

# blkid /dev/sdb1
/dev/sdb1: UUID="ad8113d7-b279-4da8-b6e4-cfba045f66ff" TYPE="ext4" LABEL="Projects"

The blkid command also display information about the device such as its UUID and label.

Each file system type supports a number of features that you can enable or disable by specifying additional options to mkfs or the build utility. For example, you can use the -J option to specify the size and location of the journal used by the ext3 and ext4 file system types.

For more information, see the blkid(8), mkfs(8), and mkfs.fstype(8) manual pages.