Well, you could just implement it yourself

sub tee {
    my ($fh1,@output) = @_;
    print $fh1 @output;
    print @output;
}

open my $fh,">","thefile.txt" or die "horribly";
tee ($fh,"What I wanted to say");
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Or use IO::Tee

use IO::Tee;

my $tee = new IO::Tee(\*STDOUT,">thefile.txt");
print $tee "What I wanted to say";
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