switch.pl

#!/usr/bin/env perl

use strict;
use warnings;
use FindBin;
use Text::MicroTemplate::File;

my $info = qx{/System/Library/PrivateFrameworks/Apple80211.framework/Versions/A/Resources/airport -I};
my ($ssid) = $info =~ / SSID: (.*)$/m;

my $mt = Text::MicroTemplate::File->new( include_path => [$FindBin::Bin] );

my $hosts;

if (-e "$FindBin::Bin/$ssid.mt" && -f _) {
    $hosts = $mt->render_file("$ssid.mt", $ssid);
}
else {
    $hosts = $mt->render_file("default.mt");
}

open my $fh, '>', '/etc/hosts' or die $!;
print $fh $hosts;
close $fh;