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LCKDO

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_TEMPFAIL 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

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