title: Maintaining same piece of code in multiple files
body: <p>I have an unusual environment in a project where I have many files that are each independent standalone scripts. All of the code required by the script must be in the one file and I can't reference outside files with includes etc.</p>
  
  <p>There is a common function in all of these files that does authorization that is the last function in each file. If this function changes at all (as it does now and then) it has to changed in all the files and there are plenty of them.</p>
  
  <p>Initially I was thinking of keeping the authorization function in a separate file and running a batch process that produced the final files by combining the auth file with each of the others. However, this is extremely cumbersome when debugging because the auth function needs to be in the main file for this purpose. So I'd always be testing and debugging in the folder with the combined file and then have to copy changes back to the uncombined files.</p>
  
  <p>Can anyone think of a way to solve this problem? i.e. maintain an identical fragment of code in multiple files.</p>