What actually happens under the hood when we execute a 'git commit' command?

When you execute git commit -m "commit message", Git performs several actions behind the scenes:

1. Gather Staged Files: Git looks at the staging area (index) to compile the snapshot.
2. Create tree objects: Creates directory structure records mapping file names to their corresponding file hashes (blobs).
3. Create a commit object: Writes a metadata file containing:
   • The hash of the root tree object.
   • The hash of the parent commit(s) (unless it is the initial commit).
   • Author and Committer names, emails, and timestamp.
   • The commit message.
4. Generate SHA-1 hash: Generates a unique 40-character SHA-1 (or SHA-256) hash identifying this commit.
5. Move HEAD pointer: Updates the pointer of the current active branch (and HEAD) to point to this new commit hash.