#!/usr/bin/perl -T

use strict;
use warnings;

# snipped directly from CGI.pm
# $val comes from (tained) URL parameters this this case
# I'm using command line input to provide tainted test input

my $val = \@ARGV;

for my $fh (grep {defined(fileno($_))} @$val) {
  seek($fh,0,0); # reset the filehandle.
}