One way is to have all your programs access the modules via pragmas of the following type:

#!/usr/bin/perl
use lib "/usr/opt/<path-to-perlmodule-folder>";
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The other way is to specify the path in each user's .bashrc or .login which is called when you login like this (you can also make an entry in /etc/bash.bashrc or /etc/login.defs or equivalent files so that new users you add automatically get it into their login rc files).

export PERL5LIB=/usr/opt/<path-to-perl5-module-folder>
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