scrub(1) --force --no-signature --pattern nnsa /dev/sdX
write patterns on disk/file
-f, --force
       Scrub even if target contains signature indicating it has already been scrubbed.
-S, --no-signature
       Do  not  write  scrub signature.  Scrub will not be able to ascertain if the disk has already been
-p, --pattern PATTERN
       Select the patterns to write.  nnsa selects patterns compliant with NNSA Policy Letter NAP-14.1-C;
       dod  selects patterns compliant with DoD 5220.22-M; bsi selects patterns recommended by the German
       Center of Security in Information Technologies (; old  selects  pre-version
       1.7  scrub  patterns;  and  fastold is old without the random pass.  gutmann is a 35-pass sequence
       described in Gutmann's paper cited below.  See STANDARDS below  for  more  detail.   random  is  a
       single  random  pass.   random2  is  two random passes.  schneier is the method described by Bruce
       Schneier in ''Applied Cryptography'' (1996) consisting of one 0x00 pass, one 0xff pass,  and  five
       random  passes.   pfitzner7  is Roy Pfitzner's 7-random-pass method.  pfitzner33 is Roy Pfitzner's
       33-random-pass method.  usarmy is the US Army AR380-19 method consisting of  one  0x00  pass,  one
       0xff pass, and a random pass.  Default: nnsa.
source manpages: scrub