use strict;
my $file;
open my $fh, "<", $file or die $!;
print "here\n";

##</code><code>##

use strict;
open my $fh, "<", $ARGV[0] or die $!;
print "here\n";

##</code><code>##

use strict;
open my $fh, "<", undef or die $!;
print "here\n";