#!/usr/bin/perl
#
# License is current GNU one.
# (c) Light Olli <olli@digger.org.ru>
#
print <<INTRO;

This will work with STDIN & translate the Cisco MAC address notation to 
common notation:

 '00D0.B7B0.2C1F' will be translated to '00:D0:B7:B0:2C:1F'

Let\'s start (^C to quit):
INTRO

while(<STDIN>)
{next 
 unless /([a-f\d][a-f\d])([a-f\d][a-f\d])\.([a-f\d][a-f\d])([a-f\d][a-f\d])\.([a-f\d][a-f\d])([a-f\d][a-f\d])/i;
 print "$1:$2:$3:$4:$5:$6\n";
}