I replaced $i with 1111 and ran the perl script, still I am getting below lines in the output file. Its not actually getting executed. COMMAND: /usr/sbin/swlist -l depot @ sidedepot.fc.com ## FILTERS: 0909 / 1111 / AR However if I run the same command on command line, its working fine. I am using the below command in the command line. /usr/sbin/swlist -l depot @ sidedepot.fc.com | grep 0909 | grep 1111 | grep AR In the script, we are not using grep, could this be the reason next unless ( /$rel_string/ and /$i/ and /AR/ ) ?????