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NAME

       setlock - runs another program with a file locked.

SYNOPSIS

       setlock [ -nNxX ] fn child

DESCRIPTION

       fn is a single argument.  child consists of one or more arguments.

       setlock  opens  fn  for  writing  (creating  it  if it does not exist),
       obtains an exclusive lock on it, and runs child.

       Normally the lock disappears when child exits.

       Here’s the complete story: child is given a  descriptor  for  a  locked
       ofile  pointing  to  the  disk file named fn.  The lock disappears when
       this ofile is

       o      closed by all the processes that have descriptors for it or

       o      explicitly unlocked.

OPTIONS

       -n     No delay. If fn is locked by another process, setlock gives  up.

       -N     (Default.)  Delay.  If  fn is locked by another process, setlock
              waits until it can obtain a new lock.

       -x     If fn cannot be opened (or created)  or  locked,  setlock  exits
              zero.

       -X     (Default.)  If  fn  cannot  be  opened  (or  created) or locked,
              setlock prints an error message and exits nonzero.

SEE ALSO

       supervise(8), svc(8),  svok(8),  svstat(8),  svscanboot(8),  svscan(8),
       readproctitle(8),   fghack(8),   pgrphack(8),  multilog(8),  tai64n(8),
       tai64nlocal(8), setuidgid(8), envuidgid(8), envdir(8), softlimit(8)

       http://cr.yp.to/daemontools.html

                                                                    setlock(8)