UNIX for Dummies Questions & Answers

export MYLOCKFILE=/path/to/mylockfile
[ ! -f  $MYLOCKFILE ]   &&  > $MYLOCKFILE    # create the file it it does not exist
pid=$(cat $MYLOCKFILE)
if [ -z  "$pid" ] ; then
   echo $$ > $MYLOCKFILE       # ok to run
else
   ps -ef | grep $pid | grep -q  $0  # see if this script is running
   if [ $? -eq 0 ] ; then   
         exit 1                        # error exit; another process is now running the script
   else
        echo ' this is a restart'
        echo $$ > $MYLOCKFILE       # ok to run
fi

echo "" > $MYLOCKFILE    # clear the lock

#!/bin/ksh
#

thisFILE="$(whence ${0})"
progName="${0##*/}"

     myPID="$$"

     FUSERout=$(fuser ${thisFILE} 2>/dev/null)
     typeset -i numProc=$(echo "${FUSERout}" | nawk '{print NF}')
     if [ "${numProc}" -gt 1 ]; then
        echo "${progName}: another instance(s) of [${thisFILE}] is currently still running [$(echo ${FUSERout} | sed -e 's/  */ /g')] - exiting THIS [${myPID}] run."
        exit 1
     fi
#
# here comes the rest of the script

#!/bin/sh
if [ $(ps -ef | grep "/myapps/app1/try/messi/cz/t.sh" | grep -v grep | wc -l) -gt 1 ]
then
        echo "Im running $(date)...exiting "
        exit 1
fi

pid=$(cat $MYLOCKFILE) if [ -z  "$pid" ] ; then    echo $$ > $MYLOCKFILE       # ok to run

 else         echo ' this is a restart'         echo $$ > $MYLOCKFILE       # ok to run