Inspecting History

git log                     # full history, newest first (q to quit)
git log --oneline           # one line per commit
git log --oneline --graph --decorate --all   # branch topology, worth an alias
git log -5                  # just the last 5 commits
git log -p                  # history WITH the diffs
git log --stat              # history with per-file change counts

git log --author="ada"              # by author (substring match)
git log --grep="login"              # by commit message
git log --since="2 weeks ago"       # by date (also --until="2026-01-01")
git log -S"apiKey"                  # pickaxe: commits that ADD or REMOVE this string
git log -G"use(Memo|Callback)"      # commits whose diff matches a regex
git log --oneline -- src/auth/      # only commits touching a path
git log --follow -- src/old-name.ts # a file's history across renames
git log main..feature               # commits on feature that main lacks

git show abc1234            # a commit's message and full diff
git show HEAD               # the most recent commit
git show HEAD~2             # two commits before HEAD
git show --stat abc1234     # files touched, no diff
git show abc1234:src/app.js # a FILE's contents at that commit

git blame src/app.js            # last commit + author per line
git blame -L 40,60 src/app.js   # only lines 40-60
git blame -w src/app.js         # ignore whitespace-only changes
git log -L 40,60:src/app.js     # full HISTORY of those lines, not just latest

git diff                        # unstaged changes
git diff --staged               # staged changes
git diff main..feature          # everything that differs between two branches
git diff main...feature         # what feature changed since it branched off
git diff --stat HEAD~3          # summary vs 3 commits ago
git diff --name-only main       # just the file names
git diff v1.0.0 v1.1.0 -- src/  # between tags, limited to a path

git bisect start
git bisect bad                  # current commit is broken
git bisect good v1.2.0          # this old ref was fine
# git checks out the midpoint: test it, then answer
git bisect good                 # or: git bisect bad
# repeat until it prints the first bad commit
git bisect reset                # return to where you started

git bisect start HEAD v1.2.0
git bisect run npm test

git tag v1.0.0                  # lightweight tag on the current commit
git tag -a v1.0.0 -m "First GA" # annotated tag (has author, date, message)
git tag                         # list tags
git tag -l "v1.*"               # filter
git push origin v1.0.0          # tags are NOT pushed by default
git push --tags
git describe                    # nearest tag + distance, e.g. v1.0.0-14-gabc1234
git describe --always           # fall back to the commit hash if no tag exists