fsck

from The Free On-line Dictionary of Computing (8 July 2008)

fsck

   1. <operating system> file system check.  The {Unix} program
   that checks a {file system} for internal consistency and bad
   blocks etc. and can repair some faults.

   fsck is often used after a {crash} when the file system has
   been left in an inconsistent state, e.g. due to incomplete
   flushing of {buffers}.

   (1998-03-06)

   2. <jargon> Used on {Usenet} {newsgroup} alt.sysadmin.recovery
   as substitute for "fuck" and became more main-stream after the
   {Communications Decency Act}.

   (1998-03-06)