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runlock



Shell script utility: runlock


This piece of code prevents multiple copies of the same program (i.e. crontab jobs) to run at the same time.

#!/bin/sh

if [ "\$1" != "1" ]; then
        # Debug
        #exit
fi

ECHO=/bin/echo
GREP=/usr/bin/grep
HOSTNAME=/bin/hostname
MAIL=/usr/bin/mail
PS=/bin/ps
RM=/bin/rm
TOUCH=/usr/bin/touch

if [ -z $MAILTO ]; then
        MAILTO="user@domain"
fi

if [ -e /tmp/$1.lock ]; then
  HOST=`$HOSTNAME`
  LIST=`$PS axuwww|$GREP \$1`
  LIST="\n\n$LIST\n"
  $ECHO "Could not execute \$1 due to lockfile...$LIST" | $MAIL -s "LOCKFILE: $HOST - error running \$1" $MAILTO
  exit 1;
fi

$TOUCH /tmp/\$1.lock

\$2

$RM /tmp/\$1.lock