title: unix redirect tail to file
body: <p>I store data from a nc output in a file 24/7 hours. It is a datalogger of temperature. 
  This file <code>amroutput</code> will be over the time very big. (Every 10 seconds a line).
  For one app I will have the last entry in a file <code>amr_last_output</code>.
  So I use:</p>
  
  <pre><code> tail -f -n1 amroutput &gt; amr_lastoutput.
  </code></pre>
  
  <p>With <code>&gt;</code> i will overwrite the file <code>amr_lastoutput</code> everytime when tal make an output.
  On mac osx we are the output of tail to the output file is appended, as in <code>&gt;&gt;</code> command.
  What can I do?</p>
  
  <p>Thanks for answers!  </p>