Linux lockfile wrapper

lockfile.sh

#!/bin/bash

# Lock file script written to ensure only once process at a time holds a lock
# Automatically kills zombie processes past the threshold
# https://gist.github.com/1350609

if [ $# -ne 3 ]; then
        echo "Usage: `basename $0` <lockfile> <timeout> <command>";
        exit 2;
fi

oldpid=0
if [ -f $1.lock ]; then
        oldpid=$(cat $1.lock)
fi

lockfile -r 1 -l $2 -s 1 $1.lock
[ $? -ne 0 ] && exit 1

if [ $oldpid -ne 0 ]; then
        kill -9 $oldpid
fi

chmod 644 $1.lock
echo $$ > $1.lock
chmod 444 $1.lock

eval $3

rm -f $1.lock