#!/bin/perl -w
    $" = '-';
    $string = "a:b c:d";
    @list = ($string =~ m/(\w):(\w)/g);
    print "list=@list\n";
    $string = "a:b:c";
    @list = ($string =~ m/(\w):(\w)/g);
    print "list=@list\n";

##</code><code>##

    list=a-b-c-d
    list=a-b

##</code><code>##

    list=a-b-b-c