Liberating GrandFather's example and twiddling it to use hostname and /etc/hosts:

#!/usr/bin/perl

use strict;
use warnings;

chomp(my $HN = `hostname`);

if (open(HOSTS, "</etc/hosts")) {
  while (<HOSTS>) {
    next if ! /^((?:\d{1,3}\.){3}\d{1,3})\s+($HN)\b/;
    print "$2: $1\n";
    last;
  }
  close HOSTS;
} else {
  die "Could not open /etc/hosts for reading: $!\n";
}
[download]

... might save a few minutes of head scratching for someone.