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Mac OS X Tiger in a Nutshell by Jason McIntosh, Chuck Toporek, Chris Stone, Andy Lester

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Name

lockfile

Synopsis

lockfile [options] filenames

Creates semaphore file(s), used to limit access to a file. When lockfile fails to create some of the specified files, it pauses for eight seconds and retries the last one on which it failed. The command processes flags as they are encountered (i.e., a flag that is specified after a file won't affect that file).

Options

-sleeptime

Time lockfile waits before retrying after a failed creation attempt. Default is eight seconds.

-!

Invert return value. Useful in shell scripts.

-l lockout_time

Time (in seconds) after a lockfile was last modified at which it will be removed by force. See also -s.

-ml, -mu

If the permissions on the system mail spool directory allow it or if lockfile is suitably setgid, it can lock and unlock your system mailbox with the options -ml and -mu, respectively.

-r retries

Stop trying to create files after retries retries. The default is -1 (never stop trying). When giving up, remove all created files.

-s suspend_time

After a lockfile has been removed by force (see -l), a suspension of 16 seconds takes place by default. (This is intended to prevent the inadvertent immediate removal of any lockfile newly created by another program.) Use -s to change the default 16 seconds.

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