I often use git add --patch as a way of interactively staging changes for a
commit. Git walks me through each individual chunk of changes—which it calls
hunks—so that I can include it or exclude it.
Sometimes, like when I'm working with a yarn.lock file, there are a ton of
computer-generated changes to a file that I don't want to individually confirm.
One of the options while interactively staging is to hit a which will stage the current hunk and all later hunks for the current file.
A complementary scenario arises at times when working with a Rails schema.rb
file. There are a bunch of Postgres client-specific changes that I don't want
to commit. Once I get to the schema.rb file, I can hit d to not stage
this or all remaining hunks in the current file.
a - stage this hunk and all later hunks in the file
d - do not stage this hunk or any of the later hunks in the file
This saves me from hitting y a dozen times to accept changes or hitting n a
dozen times to decline changes.
See man git-add and look for the Interactive mode section for more details.