In May I decided to stop using Debian's perl 5.10.1 in favor of using a 5.13.1 built with perlbrew, and CPAN modules built with cpanminus. It's been great, here's how I did it.

Before switching over I ignored Debian's perl library packages, and installed everything with cpanm into /usr/local. But since I wanted to use the new post-5.10 features of Perl I thought I might as well replace all of it and use a newer perl.

What I did:

• Created a v-perlbrew user. All users on the server can use this centrally managed Perl and its modules
• Added this to everyone's .bashrc: test -f ~/perl5/perlbrew/etc/bashrc && source ~/perl5/perlbrew/etc/bashrc
• Made a list of CPAN modules that I need. When I upgrade the perlbrew perl I can just run grep -v ^# cpan-modules | cpanm to get all the required modules with the new perl.
• Ran around changing PATH in crontabs, Apache settings etc. so that everything that isn't internal to Debian itself uses perlbrew's perl instead of /usr/bin/perl.

Getting the PATHs right everywhere turned out to be the hardest part. A lot of things in Debian have a path like /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/X11R6/bin. I haven't found out how to change that, presumably some of them are hardcoded into executables like bash.

To get around that I have to hardcode the PATH to perlbrew in every crontab that uses perl. For a full list of these and other changes I've made the output of git --git-dir /etc/.git log -p --reverse -Sperlbrew available as a Gist.

The only caveat I've encountered is that there's one global perlbrew bashrc in ~/perl5/perlbrew/etc/bashrc. So if I can't use perlbrew switch to only switch some users onto a given perl. It would be neat if perlbrew supported having the current symlinks in a local ~/perl5 while the actual binaries and modules were in ~v-perlbrew/perl5.

Since 5.12 got released a lot of bugfixes have been flowing into blead and one new feature. The prctl() support for $0 that I previously blogged about just got commited by Steffen Mueller.

With this patch you can finally killall programs you write in perl on Linux without killing all of your perl processes indiscriminately.

Jesse Vincent uploaded the perl-5.12.0-RC3 release to the CPAN. It's important that that this release is tested to flag any potential release blockers. If none are found it'll be released as 5.12 on April 9.

Here's how you can do that:

All tests should have been successful. To install it (without touching your existing perl!) do:

Now you have an installed perl-5.12.0-RC3 in ~/perl5-rc3/installed/bin/perl. Now just configure CPAN to install modules without nagging:

And then maybe try installing your favorite CPAN modules, or bundles that suck down a lot of them (using sudo here because my ~/.cpan is owned by root):

Of course the most useful think you can do is test it on your own in-house code. All the code on the CPAN has probably been tested with 5.12 already.

If you encounter any issues first check if they're listed in the errata or mentioned in the perldelta for 5.12.

if you think you've found a new bug please report it with the perlbug tool installed with perl-5.12.0-RC3.