interm: Added pages on watch and curl

git-svn-id: svn+ssh://atelier.inf.usi.ch/home/bevilj/group-1@183 a672b425-5310-4d7a-af5c-997e18724b81

site/pages/cmd/interm/curl.html

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+---
+layout: page
+category-page: intermediate
+category-title: Intermediate commands
+tags: curl download http client crawler request online 
+author: Claudio Maggioni
+title: curl
+---
+<p>
+  The <code>curl</code> command is a fast and versatile shell program that can
+  request online content using various protocols, including <em>HTTP</em>,
+  <em>FTP</em> and <em>POP3</em>. Some example use cases for this utility are 
+  the need to automate some remote call to a server, testing <em>REST</em> or
+  <em>SOAP</em> apis or simply download or display the <em>HTML</em> code of a 
+  website.
+</p>
+
+<p>
+  The name, as mentioned in the <a href="https://ec.haxx.se/curl-name.html">
+    <em>Evertything curl</em></a> online book, stands for <em>"client URL"</em>
+  and the right pronunciation rhymes with "earl" or "girl". By this fact, the
+  reader is able to tell the author of this page to stop pronuncing it as 
+  <em>"cooorl"</em>, like if the name is some sort of word in the
+  <a href="https://en.wikipedia.org/wiki/Bergamasque_dialect"><em>Bergamasque
+      dialect</em></a>.
+</p>
+
+<h3>Usage</h3>
+
+<p>
+  <code>curl</code> is a very complex command: if you want to learn it deeply,
+  please refer to the previously mentioned guide called 
+  <a href="https://ec.haxx.se/"><em>Evertything curl</em></a>. Some basic
+  ways to use this command are shown below:
+</p>
+
+<h4>Download the contents of the page "example.com" to "file.html"</h4>
+
+<pre>
+curl example.com -o file.html
+</pre>
+
+<h4>Download the contents of the page "en.wikipedia.org/wiki/Curl" to
+a file with the same name as the last element in the path (here "Curl")</h4>
+
+<pre>
+curl -O en.wikipedia.org/wiki/Curl
+</pre>
+
+<h4>Download the contents of the page "example.com" to "file.html"</h4>
+
+<pre>
+curl example.com -o file.html
+</pre>
+
+<h4>Download the contents of the page "example.com" following location
+redirects (<code>-L</code> flag)</h4>
+
+<pre>
+curl -O -L example.com 
+</pre>
+
+<h4>Download the contents of the page "example.com" resuming a previous attempt
+(<code>-C</code> flag)</h4>
+
+<pre>
+curl -O -C example.com 
+</pre>
+
+
+<h4>Do an HTTP DELETE request to "example.com" with a custom header
+(<code>-H</code> and <code>-X</code> flags)</h4>
+
+<pre>
+curl -H 'User-Agent: Tamagotchi' -X DELETE example.com
+</pre>
+
+<h4>Print to <em>stdout</em> "example.com" making a request with HTTP basic
+authentication (<code>-u</code> flag)</h4>
+
+<pre>
+curl -u bob:P@ssw0rd example.com
+</pre>

site/pages/cmd/interm/watch.html

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+---
+layout: page
+category-page: intermediate
+category-title: Intermediate commands
+tags: watch repeat track analyse seconds 
+author: Claudio Maggioni
+title: watch
+---
+<p>
+  The <code>watch</code> command is a system utility able to execute a command
+  every <em>n</em> seconds by clearing the screen and displaying the 
+  output of the command each time the interval is over. This command is very
+  simple to use and very effective: it can be used to check the size in bytes
+  of a file while downloading it, or it can be used on <em>Linux</em> to jiggle
+  around the mouse every ~5 minutes with the command <code>xdotool</code> in
+  order to keep the computer awake.
+</p>
+
+<h3>Usage</h3>
+
+<p>
+  <code>watch</code> has a very simple syntax: the amount in seconds to wait
+  between executions is specified in seconds using the <code>-n</code> flag 
+  and the default value is <em>2</em>. Also, differences between older and 
+  newer outputs are highlighted if the <code>-d</code> flag is used.
+</p>
+
+<h4>Watch the size of "ubuntu.iso" every 5 seconds</h4>
+
+<pre>
+watch -n 5 du -h ubuntu.iso 
+</pre>
+
+<h4>Watch the contents of "site.html" every 2 seconds and highlight the
+  differencies between iterations</h4>
+
+<pre>
+watch -d cat site.html
+</pre>
+