History

The history of a Git repository is a record of all commits made over time, including changes to files, commit messages, and metadata. This history is stored as a series of snapshots, with each commit representing a new version of the codebase.

Reading it

git log                    # full detail, newest first
git log --oneline           # one line per commit
git log --oneline --graph   # with branches drawn as they fork and merge

The graph view is the one to learn. On a linear history it is a single column of dots; the moment work branches, you can see where a feature left main, how far it drifted, and where it came back — which is the question git log is usually being asked to answer.

Restricting what is shown

git log -10                          # the last ten commits
git log --author="vicky"             # one person
git log --since="last monday"        # a time window
git log --grep="login"               # commits whose message matches
git log -p -- src/index.ts           # one file, with the diffs

The path filter is the most useful of these. git log -p -- <file> shows how that file reached its current state, which usually answers "why is this written this way" without any guessing.

History is per-branch

git log with no arguments shows the branch you are on. To see another branch without switching, name it:

git log main
git log main..feature-search    # on the feature branch, not yet on main

Tags mark points in it

A commit can be tagged, which gives it a name that does not move — a release, a milestone, the last version before a change. See Tagging.

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