<p>Write a bash script to calculate the frequency of each word in a text file <code>words.txt</code>.</p>



<p>For simplicity sake, you may assume:</p>



<ul>

	<li><code>words.txt</code> contains only lowercase characters and space <code>&#39; &#39;</code> characters.</li>

	<li>Each word must consist of lowercase characters only.</li>

	<li>Words are separated by one or more whitespace characters.</li>

</ul>



<p><strong>Example:</strong></p>



<p>Assume that <code>words.txt</code> has the following content:</p>



<pre>

the day is sunny the the

the sunny is is

</pre>



<p>Your script should output the following, sorted by descending frequency:</p>



<pre>

the 4

is 3

sunny 2

day 1

</pre>



<p><b>Note:</b></p>



<ul>

	<li>Don&#39;t worry about handling ties, it is guaranteed that each word&#39;s frequency count is unique.</li>

	<li>Could you write it in one-line using <a href="http://tldp.org/HOWTO/Bash-Prog-Intro-HOWTO-4.html">Unix pipes</a>?</li>

</ul>