Mac OS X in a Nutshell

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 8 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 will not affect that file).

Options

-sleeptime

Time lockfile waits before retrying after a failed creation attempt. Default is 8 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.