title: Unix sort treatment of underscore character
body: <p>I have two linux machines, on which unix sort seems to behave differently. I believe I've narrowed it down to the treatment of the underscore character.</p>
  
  <p>If I run <code>sort tmp</code>, where tmp contains the following two lines:</p>
  
  <pre><code>aa_d_hh
  aa_dh_ey
  </code></pre>
  
  <p>one machine outputs</p>
  
  <pre><code>aa_d_hh
  aa_dh_ey
  </code></pre>
  
  <p>(i.e. '_' precedes 'h') while the other outputs</p>
  
  <pre><code>aa_dh_ey
  aa_d_hh
  </code></pre>
  
  <p>(i.e. 'h' precedes '_'). I need these machines to behave together (as I use sort -m later, to merge very large files).</p>
  
  <p>Is there any way I can force sort to behave in one way or the other?</p>
  
  <p>Thanks.</p>