IO::Tee is pure Perl code. If you can copy a file onto the same machine you're running your code (and if you can't, one wonders how you're getting your code there . . .) you can "install" your own copy. Make an IO directory somewhere, put the IO::Tee source in Tee.pm, point perl at the directory containing IO via either PERL5LIB, a command line -I switch, or the standard lib module.