Semaphore - lockfile/flock Post: 302944801

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lckdo

lckdo(1)																  lckdo(1)

NAME

       lckdo - run a program with a lock held

SYNOPSIS

       lckdo [options] {lockfile} {program} [arguments]

DESCRIPTION

       lckdo runs a program with a lock held, in order to prevent multiple processes from running in parallel. Use just like nice or nohup.

       Now that util-linux contains a similar command named flock, lckdo is deprecated, and will be removed from some future version of moreutils.

OPTIONS

       -w     If the lock is already held by another process, wait for it to complete instead of failing immediately.

       -W {sec}
	      The same as -w but wait not more than sec seconds.

       -e     Execute the program directly without forking and waiting (keeps an extra file descriptor open).

       -E {nnn}
	      Set the file descriptor number to keep open when exec()ing (implies -e).

       -n     Do not create the lock file if it does not exist.

       -q     Produce no output if lock is already held.

       -s     Lock in shared (read) mode.

       -x     Lock in exclusive (write) mode (default).

       -t     Test for lock existence.

EXIT STATUS

       If the lock was successfully acquired, the return value is that of the program invoked by lckdo. If the lock couldn't be acquired, EX_TEMP-
       FAIL is returned. If there was a problem opening/creating or locking the lock file, EX_CANTCREAT or EX_OSERR will be returned.

AUTHOR

       Michael Tokarev

								    2007-08-15								  lckdo(1)