Fellow monks, has anyone worked through seamless perl upgrades on large systems?

If there's a large number of different Perl applications on a box, all using #!/usr/bin/perl (which is 5.00503) and I want to upgrade to 5.8.6, obviously I can't just replace #!/usr/bin/perl by perl 5.8.6, because that might break certain scripts only happy with perl 5.00503.

So, during a transition period, I need to support both /usr/bin/perl (5.00503) and, say, /some/other/path/bin/perl which is 5.8.6.

Old scripts are unchanged with #/!usr/bin/perl, new scripts will be using #!/some/other/path/bin/perl.

So far so good. Now let's look at the modules. Both installations are going to use different lib paths, so in order to install a new module on the box (like a security fix of a CPAN module), it needs to be installed for both perl5.00503 and perl5.8.6 (lets hope it works for both of them).

Now let's say that perl 5.10.0 becomes available. I'll add yet another perl install with its own lib directory, and now have to potentially upgrade three installs with every new module.

The problem is obviously that there's applications which no one wants to touch and therefore old perl installs have to be maintained (almost) indefinitely, slowly transitioning into a maintenance nightmare.

Has anyone in the monastry worked through transition periods like these and successfully managed them without going crazy?

In reply to Smooth perl upgrades by saintmike

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.