SHLOCK(1) | InterNetNews Documentation | SHLOCK(1) |
shlock - Create lock files for use in shell scripts
shlock [-b|-c|-u] -f name -p pid
shlock tries to create a lock file named name and write the process ID pid into it. If the file already exists, shlock will read the process ID from the file and test to see whether the process is currently running. If the process exists, then the file will not be created. shlock exits with a zero status if it could create the lock file, or non-zero if the file refers to a currently active process.
A Perl wrapper around shlock can be used via the "INN::Utils::Shlock" module.
The following example shows how shlock would be used within a shell script:
LOCK=<pathrun in inn.conf>/LOCK.send trap 'rm -f ${LOCK} ; exit 1' 1 2 3 15 if shlock -p $$ -f ${LOCK} ; then # Do appropriate work. else echo "Locked by `cat ${LOCK}`" fi
Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews after a description of HDB UUCP locking given by Peter Honeyman, and improved by Berend Reitsma to solve a race condition. Converted to POD by Julien Elie.
$Id: shlock.pod 9303 2011-08-04 22:09:57Z iulius $
2015-09-12 | INN 2.6.3 |