The other answers are better, but here's a unixy "no modules" solution just for the heck of it: 
# Usage: $teed_fh = tee @output_handles;
# Returns a new filehandle that, when written, copies to all @output_h
+andles
sub tee {
    use vars qw(*__TEE_FH);
    my $tfh = do { \local *__TEE_FH }; # XXX Should use IO::Handle ins
+tead
    defined( my $pid = open($tfh, "|-") ) or die "fork: $!";
    return select((select($tfh), $| = 1)[0]) if $pid;
    for (@_) { select($_); $| = 1 }
    while( sysread(STDIN, my $block, 8192) ) { print $_ $block for @_ 
+}
    kill 9,$$ or exit; # XXX Should use POSIX::_exit instead
}

[download]
and an example using it to do what you wanted: 
# Tee STDOUT to a log file
use vars qw(*LOG);
open LOG, ">>log.txt" or die "log.txt: $!";
*STDOUT = tee(*STDOUT, *LOG);
END { close STDOUT and wait }

# Now do something that writes to STDOUT
print "Hello, world #$_!\n" for (1..20);

# XXX But, should have just used IO::Tee in first place :)

[download]

In reply to Re: Type Globs by saucepan
in thread Type Globs by madhatter

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