til/brew/install-from-nonstandard-brewfile.md

Install From Nonstandard Brewfile

When you want to install the packages listed in the Brewfile for your current project (or dotfiles), you can run:

$ brew bundle

And brew knows to look for and use the Brewfile in the current directory.

If, however, you are trying to run brew bundle for a Brewfile located somewhere besides the current directory OR you want to target a file with a non-standard name (like Brewfile.personal), then you can use the --file flag.

$ brew bundle --file Brewfile.personal

This is what I do here in my dotfiles repo.

See man brew and find the section on brew bundle for more details.