Source : Free On-Line Dictionary of Computing

fsck
     
         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}.
     
        Used on {Usenet} {newsgroup} alt.sysadmin.recovery as
        substitute for "fuck" and became more main-stream after the
        {Communications Decency Act}.
     
        (1998-03-06)