#!/usr/bin/perl

use strict;
use warnings;
use Getopt::Std;

my $BASEDIR = "/sys/class/net";

my $USAGE = "$0 [-d] [-m] [network device regexp]

   -d  Display device address (PCI, etc)
   -m  Display MAC address

";

my %opts;
getopts("md", \%opts) or die $USAGE;

if (@ARGV > 1) {
   die $USAGE;
}
my $pattern = pop @ARGV;

opendir (BASE, $BASEDIR) or die "Unable to read $BASEDIR : $!";
while (my $dirent = readdir(BASE)) {
   next if ($dirent =~ /^\./);
   if (defined $pattern) {
      next unless ($dirent =~ /$pattern/);
   }
   my $address = `cat $BASEDIR/$dirent/address`;
   $address =~ s/\s//g;
   my $device = "none";
   if (-l "$BASEDIR/$dirent/device") {
      my $linkname = readlink "$BASEDIR/$dirent/device";
      my @path = split (/\//, $linkname);
      $device = $path[$#path];
   }
   print $dirent;
   print "\t$address"
      if ($opts{'m'});
   print "\t$device"
      if ($opts{'d'});
   print "\n";
}
closedir (BASE);