Scrub iteratively writes patterns on files or disk devices to make retrieving the data more difficult.

scrub can write patterns direct to disk, destroying any file system (preferred method), or it can write patterns on files, or on file system free space.

scrub writes NNSA NAP-14.x, DoD 5220.22-M, BSI, 35-pass gutmann, or one of several other selectable pattern sequences.

scrub operates at the POSIX system call level, thus it is portable to a wide variety of hardware platforms. However, this means it cannot do certain things like manipulate spare blocks on disks, etc..