its working now

Sorry, but I have to doubt that $in = system("snmpget ...") is really "working". system returns the command's exit code as it would be returned by wait(2). The snmpcmd manpage doesn't make any mention of exit codes, but the convention is that commands exit with 0 (zero) on success - so with the code shown in the question, $in and $out will probably be 0 most of the time, and some other number on failures.