You need to create a Net::IP object. Try this 
#!/usr/local/bin/perl
use strict;

use Net::IP;

my $ip = new Net::IP('193.0.1/24') or die (Net::IP::Error());
print ("Mask : ", $ip->mask());

[download]
PS. using strict would have prevented this error.

Update: Added IP in constructor. Directly from CPAN.

- Tom

In reply to Re: What's the bug ? by tcf22
in thread What's the bug ? by chiburashka

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