title: AWK - My regexp won't respect case
body: <p>I'm running Ubuntu 8.04 and my code looks like this...</p>
  
  <pre><code> for (i=1;i&lt;=n;i++)
   {
    if (arr[i] ~ /^[A-Z]{2,4}$/) printf(arr[i])
   }
  </code></pre>
  
  <p>I quickly discovered that the {n} expression won't work in gawk without the --posix switch. Once enabled the expression works but it is case-insenitive matching AAAA and aaaa. What is going on here?</p>