I want to use Diff only to check if files and directories exist the same in two locations but NOT compare the contents of the files themselves, because that's all I need and a regular Diff just takes too long for the amount of data. How would I go about this? Is there some other Debian standard tool that can accomplish this?
Diff: only compare if file exists, not contents
diff
You can't use diff for that. Why would your requirement be to use diff? Why do people always come to conclusions without having examined the possible solutions in detail?You could use diff -qr but that wouldn't be wise from a performance point of view if the only goal is to compare the directory structure as outlined hereOne of the answers to that question wasvimdiff <(cd dir1; find . | sort) <(cd dir2; find . | sort)whichwill give you a nice side-by-side display of the two directory  hierarchies with any common sections folded.