How does git track file changes internally?

Question

Could somebody explain how git knows internally that files X, Y and Z have changed? What is the process behind the scenes that recognizes when a file has not yet been added or h

Answer 1

I found this article very helpful.

https://codewords.recurse.com/issues/two/git-from-the-inside-out

Git is built on a graph. Almost every Git command manipulates this graph. To understand Git deeply, focus on the properties of this graph, not workflows or commands.

Extract - Make a commit that is not the first commit

The user sets the content of data/number.txt to 2. This updates the working copy, but leaves the index and HEAD commit as they are.

The user adds the file to Git. This adds a blob containing 2 to the objects directory. It points the index entry for data/number.txt at the new blob.