Simple shell script for monit to check if a lock file (containing a pid) has been left hanging around for a process that is not a daemon.

pidfile-checker.sh

#!/bin/bash

. /lib/lsb/init-functions

pidofproc "$@" &>> /dev/null

retval=$?

# Ignore cases such as retval=3 (Pid file doesn't exist)
if [ $retval -ne 1 ]
then
        retval=0
fi

exit $retval

# Can be used with monit configuration:
# check program testone with path "/etc/monit.d/libexec/pidfile-checker.sh -p /tmp/testone.pid /tmp/server.sh"
#        if status != 0 then exec "/bin/rm -f /tmp/testone.pid" 
# 
# You can add "as uid <username> group <groupname>" to the end of the exec statement if you like (I do).
# You probably want to set a sensible alert message.
#
# Note that 'with path "command args"' was only supported in some version of monit > 5.5.1 and <= 5.8.1
# before that mysterious release, you could only use commands without arguments.