#!/usr/bin/perl -w
$log_file = "logfile";
open(OLDOUT,">&STDOUT");
open(STDOUT, "| tee $log_file") or die "Can't open: $!\n";
print "Testing 1.2.3...\n";
close(STDOUT) or die "Can't close: $!\n";
open(STDOUT,">&OLDOUT");
print "done\n";
close(OLDOUT);

##</code><code>##

*Write Testing 1.2.3... to STDOUT and log_file 
*Write done to STDOUT (but NOT log_file)