title: Extract specific strings from line in file and output to another file with modifications
body: <p>New to linux and trying to escape doing this the hard way. I have a file ("output.txt") that contains the results of a 'find' command. Example first three lines from "output.txt":</p>
  
  <pre><code>/home/user/temp/LT50150292009260GNC01/L5015029_02920090917_MTL.txt
  /home/user/temp/LT50150292009276GNC01/L5015029_02920091003_MTL.txt
  /home/user/temp/LT50150292009292GNC01/L5015029_02920091019_MTL.txt
  </code></pre>
  
  <p>I'd like to use awk or sed (or similar) to extract two parts from the path listed for each line, and output to a new file ("run.txt") with extra information added on each line like so:</p>
  
  <pre><code>cd /home/user/temp/LT50150292009260GNC01; $RUNLD L5015029_02920090917_MTL.txt
  cd /home/user/temp/LT50150292009276GNC01; $RUNLD L5015029_02920091003_MTL.txt
  cd /home/user/temp/LT50150292009292GNC01; $RUNLD L5015029_02920091019_MTL.txt
  </code></pre>
  
  <p>I'm guessing this might also involve something like "cut", but I can't get my head wrapped around how to account for changing folder and file names.</p>
  
  <p>Any help would be much appreciated.</p>