macbook-pro-1:~ laurent$ diskutil eraseVolume jhfs+ "macintosh HD" disk1
Started erase on disk1 Macintosh HD
Unmounting disk
Erasing
Initialized /dev/rdisk1 as a 465 GB case-insensitive HFS Plus volume with a 40960k journal
Mounting disk
Finished erase on disk1 macintosh HD
macbook-pro-1:~ laurent$