How to list all files added to the first commit of a GIT repository?

Question

Current status: I am using git diff-tree -r HASH to list all added, modified and deleted files in a specific commit. This worked until today.

The problem: I want to list all added files in my first commit, however passing the first HASH as a parameter doesn't work. Why?

Main question: How can I get the list of all files added in my first commit?

Answer 1

This works for me

git show <commit|branch-name> --name-only