Apple - How do I format a disk partition from the command line on OS X?

diskutil list

In my case I wanted to format the parition as NTFS for installing Windows 7 on it. The last parameter is the partition 4 on first disk.

diskutil eraseVolume "Tuxera NTFS" my-ntfs disk0s4

For those of you looking to format an entire disk and remove all partitions here is the command:

diskutil eraseDisk free itsfree /dev/disk6

Even though I am formatting with free space-- I still had to give it a name for the command to work, in this case itsfree.

To list your disks

diskutil list

To securely erase - Needs to have a mounted volume

diskutil secureerase freespace 0 /dev/disk6s2

To list available filesystems

diskutil listFilesystems