Makefile.PL PREFIX=/home/gabor/perl5lib

At least this has been working well for me. All modules are now installed in the given directory instead of architecture-dependant ones and such and in the architecture dependant ones.
I am using this also in cgipan.

update: architecture-dependant directories are still used, but that's no problem for use lib. thanks to rinceWind for pointing that out.

I agree with that approach. Specifying both LIB and PREFIX works very well for me. I use install_base for Module::Build and anything that insists on it.

All modules are now installed in the given directory instead of architecture-dependant ones and such.

That's not strictly true. Pure perl modules will be installed generically to the lib directory. Modules containing XS (or Inline::C, swig, etc.) are still installed into architecture dependent paths, but this is what you want. Indeed, you can share the lib tree across platforms - I do this between Solaris and Windows, and it works too!

--

Oh Lord, won’t you burn me a Knoppix CD ?
My friends all rate Windows, I must disagree.
Your powers of persuasion will set them all free,
So oh Lord, won’t you burn me a Knoppix CD ?
(Missquoting Janis Joplin)

Oh, that seems like the good solution. I'll go and try it. I have about 400 modules installed already so I will wait a bit till all that comes back to my private perl5lib directory.

I hope it will also work with Module::Build.....

I have this problem too, and asked about it in Modules installation path. I'm using some bash to export the variable:

function P5L {
        unset PERL5LIB;
        DIRS=(~/lang/perl/modules/{lib,share}/perl/*);
        local IFS=":";
        export PERL5LIB="${DIRS[*]}";  ## double quoted array expansio
+n indexed by "*"
} && P5L
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Recently I've had to make an addition because Devel::Caller installed itself in another place:

perl Makefile.PL LIB=/home/gabor/perl5lib
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Update: Possibly you will have to specify PREFIX=/home/gabor/perl5lib or other such parameters like INSTALLSCRIPT, INSTALLBIN, INSTALLMAN3DIR as well, depending where you want these files to end up in

I don't think you need all the system perl paths in PERL5LIB. The command perl -V will list out everything that is in @INC including all the paths that were set at perl's build time (in config.pm).

Of course, you might be trying to have more than one perl on your host, and trying to share some of the library directories. I would seriously advise against that, as there could be all sorts of unforseen side effects when you come to automatically install some modules to one of the perls, see A problem with two perls on a Debian system for when I came unstuck with this.

My suggestion is to keep just the user install directories, e.g. /home/gabor/perl5lib in PERL5LIB. I've had no problems with this approach. I am in a work situation where I am installing modules to a place that doesn't require root. It's actually a Clearcase vob, but that's another story.

The module looks for a file /etc/perl5lib.pm (or %windir%/perl5lib.pm) and reads in a array ref of directories from that file.

It then massages @INC to include all relevant directories under those paths using hints from Config.pm about sitelib/privlib/archlib/vendorlib etc. without them needing to be explicitly declared.

You can download the file from here - it is too hackish to upload to CPAN as a module.

The /etc/perl5lib.pm file is in Data::Dumper format - it looks like this:

$VAR1=[
    '/opt/project1',
    '/opt/project2',
    ..
];
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Then to include all the above directories *and* any relevant vendorlib/sitelib/archlib etc directories under them in which modules may have been installed, run

perl -I/path/to/perl5lib.pm -Mperl5lib script.pl
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Or include in your script:

#!/bin/perl
use lib '/path/to/perl5lib.pm',
use perl5lib
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I did not know about the perl Makefile.PL PREFIX=<path> LIB=<path> option mentioned above though - that looks like a better idea if the modules are not already installed.