title: Replace the first line in a text file by a string
body: <p>I am a newbie at shell scripting, and am confused about how to use <code>sed</code> or any other tools to replace the first line in my text file by a string. Here are the text file contents:</p>
  
  <pre>
  /home/snehil/Desktop/j1/movie.MOV
  "spome other text lines'
  </pre>
  
  <p>I want to replace the first line (movie file path) with just <code>movie.MOV</code> (could be a variable in the shell script) </p>
  
  <p>Please guide me how to do this. I came across <code>sed</code> in some posts, do I need to use <code>sed</code> here?</p>