# display usage information if neither -f nor an address are present
if (!$options{'f'} and !$ARGV[0]) {
# display usage information if neither -f nor an address are present
if (!$options{'f'} and !$ARGV[0]) {
print "Options: -V display copyright and version\n";
print " -h show documentation\n";
print " -q quiet (no output, just exit with 0/1/2/3)\n";
print " -l extended logging\n";
print " -r test random address to verify verification\n";
print " -m <host> no DNS lookup, just test this host\n";
print "Options: -V display copyright and version\n";
print " -h show documentation\n";
print " -q quiet (no output, just exit with 0/1/2/3)\n";
print " -l extended logging\n";
print " -r test random address to verify verification\n";
print " -m <host> no DNS lookup, just test this host\n";
print " <address> mail address to check\n\n";
print " -f <file> parse file (one address per line)\n";
exit(100);
};
print " <address> mail address to check\n\n";
print " -f <file> parse file (one address per line)\n";
exit(100);
};