#!/usr/local/bin/perl

use warnings;
use strict;
use Filter::Handle qw/subs/;

#open the logfile
open (LOGFILE,">>test.log") || die "open: $!";

#set up a sub to filter our output
#print @_ to LOGFILE then also print it to STDERR
Filter \*STDERR,
	sub { local $_ = "@_"; print LOGFILE scalar(localtime), ": $_"; $_};

#test it out by printing something to STDERR
print STDERR "hello world\n";

#turn off filtering
UnFilter \*STDERR;

close LOGFILE || die "close: $!";