#!/usr/bin/perl 


use warnings ;
use strict ;

use IO::Tee;
my $log_filename = "log.txt";
my $log_filehandle;
open( $log_filehandle, '>>', $log_filename )
  or die("Can't open $log_filename for append: $!");
my $tee = IO::Tee->new( $log_filehandle, \*STDOUT );
*STDERR = *$tee{IO};
select $tee;

print "print 01\n" ;
warn "warn  02\n" ;
print "print 03\n" ;
warn "warn  04\n" ;
warn "warn  05\n" ;
print "print 06\n" ;
print "print 07\n" ;
warn "warn  08\n" ;

exit ;