lib::byversion So you have >1 Perl Installs. You have >1 Perl installs right? And you switch between running them how? Let me guess, somewhere you have code that sets a different value for PERL5LIB depending on what Perl you're using. Oh you use "perlbrew"? <http://grep.cpan.me/?q=PERL5LIB+dist=App-perlbrew> This is a slightly different approach: 1. Set up your user-land PERL5LIB directories in a regular pattern differing only by "perl" version $HOME/Foo/Bar/5.16.0/lib/... $HOME/Foo/Bar/5.16.1/lib/... $HOME/Foo/Bar/5.16.2/lib/... 2. Set the following in your %ENV PERL5OPT="-Mlib::byversion='$HOME/Foo/Bar/%V/lib/...'" 3. Done! The right PERL5LIB gets loaded based on which "perl" you use. Yes, yes, catch 22, "lib::byversion" and its dependencies need to be in your lib to start with. O.k. That is a problem, slightly. But assuming you can get that in each "perl" install somehow, you can load each "perl"'s user library directories magically with this module once its loaded. And "assuming you can get that in each "perl" install somehow" =~ with a bit of luck, this feature or something like it might just be added to Perl itself, as this is just a prototype idea to prove it works ( or as the case may be, not ). And even if that never happens, and you like this module, you can still install this module into all your "perl"'s and keep a separate "user-PERL5LIB-per-perl" without having to use lots of scripts to hold it together, and for System Perls, you may even be fortunate enough to get this module shipped by your "OS" of choice. Wouldn't that be dandy. INSTALLATION This is a Perl module distribution. It should be installed with whichever tool you use to manage your installation of Perl, e.g. any of cpanm . cpan . cpanp -i . Consult http://www.cpan.org/modules/INSTALL.html for further instruction. Should you wish to install this module manually, the procedure is perl Makefile.PL make make test make install COPYRIGHT AND LICENSE This software is copyright (c) 2017 by Kent Fredric <email@example.com>. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.