title: Regular Expression : bash 3 vs bash 4
body: <p>The follow code with a regular expression check does not outputs the same result between bash 3 and bash 4: </p>
  
  <pre><code>TESTCASE="testcase0"
  [[ ${TESTCASE} =~ "^testcase[0-9\.]*$" ]]
  echo $?
  echo ${BASH_REMATCH}
  </code></pre>
  
  <p>bash 3.2 outputs a successful regular expression check:</p>
  
  <pre><code>0
  testcase0
  </code></pre>
  
  <p>bash 4.1 fails the regular expression check:</p>
  
  <pre><code>1
  &lt;empty line&gt;
  </code></pre>
  
  <p>I can't identify where in my regex pattern the expressions fails. I would need a code compatible between both version of bash. </p>
  
  <p>Does anyone have a clue on what's my problem ?</p>
  
  <p>Thanks ! </p>