title: Sorting text file
body: <p>I've this txt file (almost 60 MiB)</p>
  
  <pre><code>560000100300100201100001000000000000[...]
  560000100400100201100001000000000000[...]
  560000100400200201100001000000000000[...]
  560000100200100201100001000000000000[...]
  </code></pre>
  
  <p>i'm writing an app in vb .net that do some unrelated process with this file.</p>
  
  <p>But at the end, it's unsorted.</p>
  
  <p>The "keys" are: (they're together)</p>
  
  <pre><code>01003, 01004, 01004, 01002
  </code></pre>
  
  <p>and </p>
  
  <pre><code>001, 001, 002, 001
  </code></pre>
  
  <p>Every line starts with 56000 then the first key, the the second key and the rest of the line.</p>
  
  <p>I tried to use SORT, that's included with Windows. It does a pretty nice job, but i need to have my own function in case SORT is not available.</p>
  
  <p>The output should write 560001002001 at first.</p>
  
  <p>Any ideas?, ask whatever you need yo know.</p>
  
  <p>Thank you.</p>