Check for missing files in two directories and their respective subdirectories

Question

Folder alpha has one subfolder, and files in both root and in subfolder.

Folder beta has 25 subfolders with files in them.

How would I compare the file contents of alpha and beta, checking for difference in files?

Answer 1

Assuming the file and directory names don't have newlines in them:

diff  <(cd alpha ; find . -type f) <(cd beta; find . -type f)

The find commands list the files in the directories the cd changed to and the diff compares the listings. Output looks like:

1c1,2
< ./b/c/file.x
---
> ./b/c/file.d
> ./b/c/file.e

with < indicating files only in alpha and > only in beta