title: PERL 'e' (eval) within REGEX error when using lt (<)
body: <p>I am using a one liner from the command line to do a REGEX substitution. This works:</p>
  
  <pre><code>perl -pe 's/&lt;span class="num"&gt;(\d\d?)/&lt;span class="num"&gt;+$1 + 1/eg' calendar1.html  &gt; output.html
  </code></pre>
  
  <p>But when I add <code>&lt;td&gt;</code> to the beginning I get error:</p>
  
  <pre><code>perl -pe 's/&lt;td&gt;&lt;h3 class="day"&gt;&lt;span class="num"&gt;(\d\d?)/&lt;td&gt;&lt;h3 class="day"&gt;&lt;span class="num"&gt; +$1 + 1/eg' calendar1.html  &gt; output.html
  </code></pre>
  
  <p>Error:</p>
  
  <pre><code>Can't modify numeric lt (&lt;) in scalar assignment at -e line 1, near "1}"
  </code></pre>
  
  <p>The html structure I am trying to match looks like this:</p>
  
  <pre><code>&lt;td&gt;
        &lt;h3 class="day"&gt;&lt;span class="num"&gt;10
  </code></pre>
  
  <p>I am trying to 1 to each one or two digit number</p>