while (<SNMP>) {
    next if /^#|^\s*$/;
...

##</code><code>##

while (<DATA>) {
    print "$1\n" if /^snmpmanager\s+(\d+\.\d+\.\d+\.\d+)\s+;\s+communityname/;
}

__DATA__
#test file
#example:
snmpmanager 10.52.37.99 ; communityname public