(I'm reviewing for Andrew since he's out of office and probably didn't see your pull request yet.)

Can you add a feature guard? preput is only supported on some Readline implementations.

    if($command =~ /^\/e(?:dit)?$/i) { 
        if($term->Features->{preput}) {
            # remaining
        } else {
            print "Your Term::Readline implementation does not support preput. Install Term::Readline::GNU from CPAN.\n";
        }