Re: Question about perl organisation on disk and CPAN
On 4/3/08, Lesley Binks <lesley.binks@googlemail.com> wrote:
> Hi
>
> I'm using Perl 5.8.8 on etch and I have a couple of questions about Perl.
>
> My @INC is
> @INC is /etc/perl /usr/local/lib/perl/5.8.8
> /usr/local/share/perl/5.8.8 /usr/lib/perl5 /usr/share/perl5
> /usr/lib/perl/5.8 /usr/share/perl/5.8 /usr/local/lib/site_perl
> and, as far as I understand it this describes where perl searches for modules.
>
> The major difference between Debian etch and other distros I have
> worked on is the existence of /etc/perl which contains subdirectories
> of CPAN and NET on my install.
>
> Almost all other distros share the /usr/share and /usr/lib hierarchies
> and I would like to know why the two hiearchies exist and how it is
> decided which hiearchy a module will be installed.
> Basically what characteristics does a module have which means it
> belongs in /usr/share or /usr/lib?
>
> I think I understand the /usr/local hierarchy as a place to put
> anything that occurs locally - any locally written modules and I use
> site_perl for web related modules - mod_perl for example.
>
> I can see the latest release of perl is 5.10 so presumably one could
> have perl/5.10.0 as well as perl/5.8.8 on one installation but there
> might be some modules that are generic across all perl 5.x releases.
>
> The last question relates to installing modules. Debian provides the
> apt-get mechanism, and the cpan mechanism can also be used in two ways
> 'perl -MCPAN ..' or just using cpan on the command line.
>
> I assume I get the modules that have been released with etch and which
> might be a few versions behind the latest for any given module when
> using the apt-get option e.g. 'apt-get libcgi-perl'.
>
> If I use CPAN what is the best method to use? Should I use the cpan
> command or should I use the perl -MCPAN method? And how much of a
> problem is not having perl 5.10 installed going to be if I choose to
> get the latest modules from CPAN? Is it possible to install 5.10 on
> etch or are there dependencies that might have wider effects than
> simply updating perl e.g. altering the libraries that gcc relies on?
I think you might run into some issues if you install perl 5.10, but I am
not a perl expert.
As far as installing stuff from cpan, I suggest you check out a program
called dh-make-perl. It wraps cpan to create a .deb of the module, so
you can use the package manager to manage your cpan modules. It is
clearly easy to use, since I got it to work without much trouble and I
know almost nothing about perl or cpan.
Cheers,
Kelly Clowers
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