#!/usr/bin/perl
    use strict;
    use warnings;
    use File::Slurp;

    my $file1 = shift
        or die "Usage: $0 file1 < another-file";
    my $nets = join "|", map { chomp;
                               /^Net '([^']+)'/ and $1 or ()
                             } read_file($file1);

    /$nets/
        or print
      while <STDIN>;