If you simply make sure that ~/myperl is not in your path (or root's path for that matter), you'll never be bothered by it again unless you want to.

You can even run specific scripts with the 5.8.x release either by typing ~/myperl/perl your-script.pl or putting #!~/myperl/perl as first line in the script.

Incidently, please don't take this as an offence, but this is not a Perl problem, but rather UNIX related, so I think it would help if you read a bit more on that subject.

Hope this helps, -gjb-