root@boiao:~# perlbrew list
* /usr/local/bin/perl (5.10.1)
  /usr/bin/perl (5.12.4)
[download]

Those aren't Perls that perlbrew has control over. I found this confusing the first time I used it. Once you install a Perl with perlbrew and switch to it, you see'll the list change. Something like this:

* perl-5.12.4
  /usr/local/bin/perl (5.10.1)
  /usr/bin/perl (5.12.4)
[download]

When you do the installation, you're probably going to want a little more than

perlbrew install perl-5.12.4
[download]

perlbrew (CPAN) documents the general and install-specific options. Also take a look at the two config_args='...' in your perl -V outputs: they differ widely. The perl 5.12.4 INSTALL file may be useful in deciding which -D options to use. You can give each installation its own name with the --as option. So, your actual command might look a bit more like:

perlbrew install -v perl-5.12.4 -Dusethreads -Duselargefiles --as perl
+-5.12.4_custom
[download]

You can now switch to the Perl you've installed. (More on this below.)

If you didn't choose a custom name, your list will now look like what I showed above. If you did use --as, you'll now see

* perl-5.12.4_custom
  /usr/local/bin/perl (5.10.1)
  /usr/bin/perl (5.12.4)
[download]

I noticed you were trying many variations for the switch statement argument. Given the above, the correct incantations would be:

perlbrew switch perl-5.12.4         # --as not used
perlbrew switch perl-5.12.4_custom  # --as used
[download]

You may find this thread useful after installation: perlbrew: moving to a new perl with all current modules

$ perlbrew available
  perl-5.17.1
  perl-5.16.0
  perl-5.14.2
  perl-5.12.4
  perl-5.10.1
  perl-5.8.9
  perl-5.6.2
  perl5.005_04
  perl5.004_05
  perl5.003_07
$ perlbrew install perl-5.16.0
[download]

Also, is this a machine that many people use or is it your personal machine? By default, perlbrew installs itself and perl in your home directory, so you don't need to ever use sudo when adding new modules; however, for our shared workhorse, I follow the docs at http://perlbrew.pl to install into /perlbrew so that everyone is able to use the modules I install.

I would rather get rid of 5.10.1 completly and use 5.12.4 as system default, as this is also used by the webserver processes.


root@boiao:~# perlbrew switch
No version in use; defaulting to system

Since the dist-upgrade changed perl configuration, surely there must be some way to force the system defaults ?
Any advice to this is greatly appreciated.
Br, Jimmy

Is 5.10.1 what came with your OS? If so, I strongly recommend against messing it up.