[~] # perl -MYAML -E 'say $INC{"YAML.pm"} # Please'
/opt/lib/perl5/site_/5.14.2/YAML.pm # you're welcome!
[download]

To be honest, I am confused about library path settings
During perl install I was asked this question and entered config as shown below:

1. Pathname where the private library files will reside? (~name ok)
[/opt/lib/perl5/5.14.2]
[download]

-->so is this the same as the cpan <mbuildpl_arg> setting...so if not already set, when using CPAN should I set:

cpan> o conf makepl_arg "PREFIX=/opt"

2. Another question during the perl install was:

Pathname for the site-specific library files? (~name ok)
[/opt/lib/perl5/site_/5.14.2]
[download]

--> does this relate to any of the 'o conf' settings?

3. Another question I have is...can you set such parameters as cpan's <cpan_home>, <build_dir>, <mbuildpl_arg> or <makepl_arg> during a tarball installation of perl?
The problem is that I am installing it on a qnap NAS device in which /root is on a RAM drive with limited space. You can't accept the default settings. I was hoping to write the steps up on the qnap forum.

4. A final question which arose from another posting here is, should I have set:

cpan> o conf mbuildpl_arg "--install_base /opt"

and how does this differ from

cpan> o conf makepl_arg "PREFIX=/opt" )

?

Thanks