title: execl() arguments in Ubuntu
body: <p>I am learning linux programming and came across exec function which is kind of very useful. But the problem is exec function arguments are very confusing and I am unable to grasp which argument is for what purpose.. In the following code <code>execl()</code> function is called from a child created through <code>fork()</code>, What is the purpose of the last argument (<code>NULL</code>) in <code>execl()</code>?</p>
  
  <pre><code>execl("/bin/ls","ls","-l",NULL);
  </code></pre>
  
  <p>If any one can explain what is the purpose of <code>NULL</code> argument and other arguments and the purpose of arguments of <code>exec()</code> family function, It would be a great help to me!</p>