Navigate to Applications > Utilities and choose Disk Utility.
Select the drive you want to format from the left-hand navigation menu. Click Erase in the bottom right-hand corner.
Select a file system to format the drive with. If you're not sure, Mac OS Extended (Journaled) is a safe bet. Choose a new name for the formatted drive and click Erase.
|Mac OS Extended (Journaled)||JHFS+|
|Mac OS Extended||HFS+|
Navigate to Applications > Utilities and choose Terminal.
diskutil list and press enter. This will provide a list of hard drives attached to the machine. Locate and note the name of the drive you want to format.
You can use the
diskutil eraseDisk command to format a harddrive. Run the following command, be sure to make adjustments for your drive. Replace
JHFS+ with any file system you need (check the chart above for a list of file systems you can use). Replace
CleanDrive with the new name for your formatted drive. Put your disk name in place of
diskutil eraseDisk JHFS+ CleanDrive /dev/disk1