Linux Shell Script to Compare PID

Just my testing Linux bash script code to compare PID... I'm not really using it yet. But I'm thinking if I can use it to verify that there is running process with the same PID in /var/run/appname.pid on the running process snapshot (ps).


if there is no such PID, maybe I can simply delete the .pid file. And the process which will check for this file can restart as usual.

Here's the content of my ~/pidcmp script:

#!/bin/sh

thepid=`cat /var/run/ppp0.pid`
echo "the pid is $thepid"
spsaux=`ps aux | grep [p]ppd`
okflag=0

gettx ()
{
   local IFS=" "
   i=0
   for tx in $1; do
      myarr[$i]=$tx
      let i+=1
   done
}
NEWLINE='
';
oldifs=$IFS
IFS=$NEWLINE
for line in $spsaux; do
#   echo "line: $line"
   gettx $line
   foundpid=${myarr[1]}
   if [ $foundpid == $thepid ]; then
      echo "the pid is equal!!"
      okflag=1
   fi
done

#echo "foundpid: ${myarr[1]}"
IFS=$oldifs

echo "okflag = $okflag"

This is just my idea... The script is working for that purpose but use it at your own risk... Enjoy Linux bash scripting!!