title: Convert between byte count and "human-readable" string
body: <p>Is there a shell command that simply converts back and forth between a number string in bytes  and the "human-readable" number string offered by some commands via the <code>-h</code> option?</p>
  
  <p>To clarify the question: <code>ls -l</code> without the <code>-h</code> option (some output supressed)</p>
  
  <pre><code>&gt; ls -l 
    163564736 file1.bin
        13209 file2.bin
  </code></pre>
  
  <p>gives the size in bytes, while with the <code>-h</code>option (some output supressed)</p>
  
  <pre><code>&gt; ls -lh 
    156M file1.bin
     13K file2.bin
  </code></pre>
  
  <p>the size is human readable in kilobytes and megabytes. </p>
  
  <p>Is there a shell command that simply turns <code>163564736</code>into <code>156M</code> and <code>13209</code> into <code>13K</code> and also does the reverse? </p>