runlock(1) prevent concurrent execution of a process


runlock [ -h ]

runlock [ -d ] [ -f pathname ] [ -t timeout ] command [ args ]


runlock tries to hold an exclusive lock while it executes a command. Subsequent execution of runlock with the same lock, while that lock is held, will cause the new instance of runlock to terminate with a faliure exit code. Otherwise, the exit code of the subprocess is returned.



Debug mode; send log messages to standard error as well as to the system log.

-f pathname

Specifies the pathname of the file to use as a lock file. The default is to create a lock file in /tmp/cronutils-$USER with the name of the command, and suffix ".pid".

-t timeout

Specifies the duration, in seconds, for runlock to wait before giving up on trying to acquire the lock. The default is 5 seconds.


Prints some basic help.


Sending SIGALRM to runlock before the timer has expired will cause the subprocess to be killed.


runlock was written by Jamie Wilkinson <[email protected]>.


This program is copyright (C) 2010 Google, Inc.

It is licensed under the Apache License, Version 2.0