title: Output file with one byte per line in hex format (under linux bash)
body: <p>As the title says, here is an example:</p>
  
  <pre><code>$ cat test.txt 
  ABCD
  $ hd test.txt 
  00000000  41 42 43 44 0a                                    |ABCD.|
  00000005
  </code></pre>
  
  <p>my desired output would be:</p>
  
  <pre><code>41
  42
  43
  44
  </code></pre>
  
  <p>I know that this is possible with sed, awk and stuff, but this might be very slow for large files. I thought of an format string for "hexdump" or a parameter combination for "od". Could you please help me out?</p>