Ignore specified modifications when git add

Question

There are currently two branches, master and b branch
Every time a file is modified, a lot of files will be generated after compilation, and some of the files need to be submitted to the master branch, and some need to be submitted to the b branch
How to ignore the files of another branch when executing git add under a certain branch

Answer 1

Just configure different .gitignore for the two branches.

Answer 2

git add + the file name you need to submit