format/Erase Equivalence Disk Utility and Terminal Command diskutil
The equivalent commands are given below.

diskutil eraseDisk MS-DOS GPT diskX
diskutil eraseDisk MS-DOS MBR diskX


Where diskX is the identifier for the drive. The value of X needs to be replaced with a integer of 0 or higher. The command diskutil list will list all the current disk identifiers. The command diskutil listfilesystems will list the available formats.