title: How to run a github javascript
body: <p>I'm looking for a node js code to read and write in one text file. On guthub I have found a promising script from Arahnoid:</p>
  
  <p><a href="https://gist.github.com/Arahnoid/9925725#file-read-write-file-js" rel="nofollow">https://gist.github.com/Arahnoid/9925725#file-read-write-file-js</a></p>
  
  <p>If I try to execute it, I get the error "File is not defined (line 3 ... new file(txt...). I guess, I have to install a npm package. But I don't know which one.</p>
  
  <p>Can anybody give my a hint how I get to run this javascript?</p>