improve gw-dev and add gw-devs

New version doesn't rely on antiquated Perl.

bin/gw-dev

@@ -1,27 +1,3 @@
-#!/usr/bin/perl
+#!/bin/bash
 
-use strict;
-use warnings;
-
-use List::Util qw(first);
-
-my @devs = ();
-open(ROUTE, "route -n |") or die "fork route -n failed: $!\n";
-while(<ROUTE>) {
-  next unless /^0\.0\.0\.0 /;
-  my @F = split /\s+/, $_;
-  push @devs, $F[7];
-  #warn "# $F[7]\n";
-}
-close(ROUTE) or die "route -n failed: $!\n";
-
-sub choose_if_valid {
-  my ($dev) = @_;
-  return unless $dev;
-  print "$dev\n";
-  exit 0;
-}
-
-choose_if_valid($devs[0]) if @devs == 1;
-choose_if_valid(first { /eth\d/ } @devs);
-choose_if_valid($devs[0]);
+gw-devs | head -n 1

bin/gw-devs

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+ip route | ruby -lne 'puts $1 if /^default .* dev (\S+)/'