Read the project history

The commit history tells you which snapshots exist and how they connect.

Start with a compact view:

git log --oneline

Each line shows an abbreviated commit ID and its subject. The newest reachable commit appears first.

To see branch and tag names beside their commits, add decorations:

git log --oneline --decorate --graph --all

--all asks Git to start from all local references, not only HEAD. --graph draws the parent relationships. It does not change history.

Inspect one commit

Inspect one commit in detail with:

git show --stat <commit-id>

Then use git show <commit-id> to inspect its patch.

You only need the first few characters of a commit ID. Git accepts any unambiguous prefix.

History is read-only, so these are safe commands when you feel lost. If a change seems to have disappeared after switching or resetting, inspect git log --all before trying another modifying command.

git log follows the current branch by default. If you switched away from a feature branch, its commits might not appear until you add --all or check out that branch again.

Filter history when the list gets long:

git log --oneline -- README.md

That shows only commits that touched README.md. Handy when you want to know who last changed one file.

Another useful filter is by author:

git log --oneline --author="Flavio"

History commands never modify data. Run them freely when you are unsure what happened.

You can also limit how many commits appear:

git log --oneline -5

That is useful on repositories with years of history. Start small, then widen the search when you need more context.

Try this on your own project: find the commit that introduced one file. Read its message, parent, and patch. Can you explain the project state before and after it?