title: What does the line "#!/bin/sh" mean in a UNIX shell script?
body: <p>I was going through some shell script tutorials and found the following sample program:</p>
  
  <pre><code>#!/bin/sh
  clear
  echo "HELLO WORLD"
  </code></pre>
  
  <p>Can anyone please tell me what the significance of the comment <code>#!/bin/sh</code> at the start is?</p>