#!/usr/bin/env perl

use v5.14;

tee("/tmp/foo", "/tmp/bar", "/tmp/glarch");

while (<>) {
		print "$ARGV at line $. => $_";
}

close(STDOUT) || die "can't close STDOUT: $!";

sub tee {
		my @output = @_;
		my @handles = ();
		for my $path (@output) {
				my $fh; # open will fill this in
				unless (open ($fh, ">", $path)) {
						warn "cannot write to $path: $!";
						next;
				}
				push @handles, $fh;
		}
		# reopen STDOUT in parent and return
		return if my $pid = open(STDOUT, "|–");
		print "\$pid is : $pid";
		die "cannot fork: $!" unless defined $pid;
		# process STDIN in child
		while (<STDIN>) {
				for my $fh (@handles) {
				print $fh $_ || die "tee output failed: $!";
				}
		}
		for my $fh (@handles) {
				close($fh) || die "tee closing failed: $!";
		}
		exit; # don't let the child return to main!
}