Redirecting old file URLs (no pattern) running Drupal 7.65. 

Our previous website manager moved us from Drupal 6 to Drupal 7 and cleaned up the file structure on our server.

While all the files that are now on our website have clean and organised URLs, and all general URLs on our website are now clean, Google still has indexed our old URLs.

e.g.: 


  old: domain.com/program-name 
  
  new: domain.com/programname


and


  old: domain.com/sites/default/files/documents/owl-final-final3.pdf
  
  new:
  domain.com/sites/default/files/folder1/folder2/owlguide.pdf


So if someone googles 'program name' or googles for our 'owl guide', the Google result takes them to the old URLs (broken links) rather than the new URLs. 

Is there a way I can redirect these broken links to e.g. a search page on our website, rather than the "404 page not found" page? 

For some of the old URLs to our pages (e.g. /program-name rather than /programname) I've been able to set up URL aliases to redirect people but don't know how I can do so for the files when there are so many that I wouldn't be able to work out. 

Sorry if I haven't used the right words, I'm not a web developer! I looked into Pathologic but don't think it addresses the problem we're having...
Goto http://YOURSITE/admin/config/system/site-information and under "ERROR PAGES
" change "Default 404 (not found) page" to your search page. In this way, Drupal will redirect all 404 pages to the page that you have provided.