title: What does "/dev/null" mean at the end of shell commands
body: <p>What is the difference between the following commands?</p>
  
  <pre><code>ssh myhostname "command1; command2;...commandn;" 2&gt;/dev/null
  ssh myhostname "command1; command2;...commandn;" 
  </code></pre>
  
  <ol>
  <li><p>what does <code>2&gt;</code> mean?</p></li>
  <li><p>what does <code>/dev/null</code> mean? I read somewhere that result of command will be write to file <code>/dev/null</code> instead of console! Is it right? It seems strange for me that the name of file be <code>null</code>!</p></li>
  </ol>