This is the command shlock that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator
PROGRAM:
NAME
shlock - create lock files for use in shell scripts
SYNOPSIS
shlock -p pid -f name [ -b ] [ -u ] [ -c ]
DESCRIPTION
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 if
the process is currently running. If the process exists, then the file will not be
created.
Shlock exits with a zero status if it was able to create the lock file, or non-zero if the
file refers to currently-active process.
OPTIONS
-b Process IDs are normally read and written in ASCII. If the ``-b'' flag is used,
then they will be written as a binary int. For compatibility with other systems,
the ``-u'' flag is accepted as a synonym for ``-b'' since binary locks are used by
many UUCP packages.
-c If the ``-c'' flag is used, then shlock will not create a lock file, but will
instead use the file to see if the lock is held by another program. If the lock is
valid, the program will exit with a non-zero status; if the lock is not valid
(i.e., invoking shlock without the flag would have succeeded), then the program
will exit with a zero status.
EXAMPLES
The following example shows how shlock would be used within a shell script:
LOCK=/run/innd/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
HISTORY
Written by Rich $alz <rsalz@uunet.uu.net> after a description of HDB UUCP locking given by
Peter Honeyman. This is revision 1.9, dated 1996/10/29.
SHLOCK(1)
Use shlock online using onworks.net services