There may be some reasons to keep older versions of perl lying around (older code that uses it, other libs compiled against it, etc).

But I can definitely think of one reason to have more than one instance of perl on the same system even if they are of the same version. If you are trying to run mod_perl 1.x and mod_perl 2.x on the same machine I would almost emphatically recommend using two different instances of perl since you will have some modules with the same name (Apache::Request for example) that are completely different versions (meaning A::R 1.x will not work with mod_perl 2.x and vice versa).

In reply to Re^4: Sysadmin questions on efficient installation of new Perl versions by mpeters
in thread Sysadmin questions on efficient installation of new Perl versions by Anonymous Monk

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.