title: Fast append before string on each new line
body: <p>I have a couple of pretty large text-files (1 GB each) which have one generated word on each line. I want to append a string before each of the generated words. Whether it's Java, C#, C, C++, or Ruby doesn't really matter. While I can't program this myself, I can compile and run it.</p>
  
  <p>Example:</p>
  
  <p>file.txt:</p>
  
  <pre><code>Aoos
  ahsd
  gAATa
  sdFfg
  </code></pre>
  
  <p>output:</p>
  
  <pre><code>appendAoos
  appendahsd
  appendgAATa
  appendsdFfg
  </code></pre>
  
  <p>Any help is welcome!</p>