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setlock(8)                  System Manager's Manual                 setlock(8)

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), ob-
       tains 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,  set-
              lock 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)