zerofree(8) on Linux
The text 598777f83458, as Debian 7 (Wheezy) shipped it.
zero free blocks from ext2, ext3 and ext4 file-systems
Flags it lists
-
-f -
-n -
-v
The text 598777f83458, as Debian 7 (Wheezy) shipped it.
zero free blocks from ext2, ext3 and ext4 file-systems
-f
-n
-v