git add -A vs git add file

Question

I got into the habit of using .gitignore and always doing git add -A, git status to check the modified files, then commit, so I don't need to remember about the files that I have modified and other developers don't need to know which files are ignored.

I still see other people doing git add files for each modified file.

So I was wondering whether there is any advantage of adding each file.

The question is: why not always using git add -A ?

Answer 1

When you are developing a feature, you may also fix some bugs or misspells that you found while browsing the code. Those corrections are not directly related to your feature, so maybe you want a separate commit for them. git add [something] allows you to work in this way.

Answer 2

Sometimes it's useful to be able to have a file in the git repository, not have it listed in .gitignore, and make local changes that you don't want to commit.

For me, this applies for example to Django's settings.py files, where I sometimes make changes to accommodate local database settings and the like. You still need to occasionally change bits of those files, e.g. adding bits to INSTALLED_APPS, which you can still commit using git add -p. The alternative would involve having a settings.py.example file, and adding settings.py to .gitignore, but then you need to manually "merge" changes from the example file into your actual settings file. If you haven't changed settings.py, you can just use git add .

Another use-case is if you have made two sets of changes, which you want to commit independently of each other. Then you can use git add [-p] <file>, commit, and repeat, as appropriately. Of course you need to ensure that your diffs are truly independent.