How to create ext2, ext3, and ext4 partition.

Once you’ve partitioned your hard disk using fdisk command, use mke2fs to create either ext2, ext3, or ext4 file system.

Create an ext2 file system:
mke2fs /dev/sda1

Create an ext3 file system:
mkfs.ext3 /dev/sda1
(or)
mke2fs –j /dev/sda1

Create an ext4 file system:
mkfs.ext4 /dev/sda1
(or)
mke2fs -t ext4 /dev/sd