In Git, how do git add -A, git add -u, and git add . differ?

## Two independent axes Candidates usually memorise three commands and get them confused because they are really two questions asked at once. **Axis one — do untracked files count?** `-u` says no: only paths that already have an index entry are considered, so modifications and deletions are staged and a newly created file is left alone. `-A` and a plain pathspec both say yes: new files are added along with everything else. **Axis two — how much of the tree?** `-A` with no pathspec covers the entire working tree no matter where you are standing. `.` is a pathspec meaning the current directory and below, so running it from a subdirectory quietly ignores changes elsewhere in the repository. `-u` with no pathspec also covers the whole tree in modern Git. Once you see the two axes, the combinations are obvious: `git add -A .` is all-changes limited to this subtree, and `git add -u src/` is tracked-only limited to `src/`. ## The deletion trap and its history The classic confusion is whether these commands notice a file you deleted with `rm`. In Git 2.x they all do within their scope — a deletion is just another change to stage. This was not always true: older Git treated `git add .` as "add and update", silently skipping removals, which is why so much folklore still insists you must use `-A`. If you find advice claiming `git add .` misses deletions, it predates Git 2.0. Running against an old Git, or writing a script that must behave identically everywhere, is the one case where spelling out `git add -A` is worth the keystrokes. ## Choosing in practice Blanket staging is convenient and occasionally embarrassing. Two habits keep it safe. First, run `git status --short` before any blanket add and read the `??` lines. Those are the untracked files that `-A` and `.` will sweep in — a `node_modules` directory, a local dump file, an editor scratch file. If you see them, fix the ignore rules rather than reaching for `-u` as a workaround; `-u` hides the problem from this commit but not from the next person. Second, remember that these commands say nothing about what *belongs* in the commit. Staging everything at once is the opposite of composing a commit: it produces a diff with several intents in it, which reviewers and later bisects both pay for. For a mixed working tree, hunk-level staging is the tool; blanket adds are for when you have already checked that everything on the list is one change. ## Related spellings `git commit -a` is roughly `git add -u` followed by a commit — tracked modifications and deletions only, no new files. That is why a new file you forgot to add keeps missing your commits. Pathspec magic gives finer control: `git add :/` stages from the repository root regardless of your current directory, and `git add ':(exclude)*.log'` stages everything but the matching paths. Both are useful when a blanket add is nearly right but not quite.