#!/usr/bin/perl -w
use strict;

while (<DATA>) {
    my ($host, $test) = ($_ =~
      m/
        (                      # Start first capture
          [\w\-]+              # One or more alphanum or hyphens
          (?:                  # non-capturing lookahead
            ,my-domain,com     # Literal string
          )?                   # Make it optional
        )                      # End of first capture
          (?:                  # non-capturing lookahead
            [\w\-,]+           # One or more alpanum or hyphens
          )?                   # Make it optional
        \.                     # A literal period
        (                      # Start second capture
          [a-z]+               # One or more lowercase chars
        )                      # End second capture
     /x)
        or print "Cannot parse $_\n" and next;

    print "Host:$host Test:$test\n";
}

__DATA__
hosta-sel-kr-1,my-domain,net.testa
hostb-sel-kr-1,my-domain,net.testb
hostc-sel-kr-1,my-domain,com.testa
hostd-sel-kr-1,my-domain,com.testc
hoste-sel-kr-1,my-domain,net.testxyz
hosta-mel-au-1,my-domain,net.testabc
hosta-mel-au-1,my-domain,net.testdef
hostxyz.testabc
someotherhost.someothertest