What's in core varies from one version of perl to another, so unless you also nail down *exactly* what version of perl your application is for, then you may need to be a bit clever about core modules. But only a bit clever, cos it's pretty easy really.

For every module that you depend on, including core modules, check to see if a recent enough version of it is installed. If not, add it to the list of modules that you need to install. Many core modules (at least of those which haven't been in core since forever) are dual-lived so also exist independently on the CPAN.

Your script will end up looking something like this ...

#!/usr/bin/perl

use strict;
use warnings;
use CPAN;

my %needed = (
  Some::Module => 1.23, # must have at least version 1.23
  Other::Module => 0, # any old version will do
  ...
);
my @need_to_install = ();
foreach my $module (keys %needed) {
  eval "use $module;";
  if($@ || eval "${module}::VERSION < $needed{$module}") {
    push @need_to_install, $module;
    next;
  }
}
CPAN::Shell->install(@need_to_install);
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