Be careful. The line endings in your database could be inconsistent. Try: 
s/\r\n?|\n\r?/<br>/g;

[download]
which should work no matter which line ending is in the database whether you are on Windows, Unix, or a Mac.

If you are (as it looks) trying to define a set of conversions for turning text into somewhat equivalent HTML, you might also want to look at Parse::RecDescent for a much better way to do parsing than just throwing a few regular expressions at it. Or you can go for the hand-rolled version at Why I like functional programming (see the bottom of the thread for a cleaner rewrite through). The rule here could be done by adding the handler 

sub {'<br>'}

[download]
for each of "\r\n", "\n\n", "\r", and "\n". Why would you do that you ask? Well because with that code you can readily implement markup rules based on user defined choices without getting into a mess of custom logic.

In reply to Re (tilly) 3: Strange values in hash reference by tilly
in thread Strange values in hash reference by filmo

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.