Point Homebrew to a local package instead of the default, remote one I'm trying to pull down and install the Alpine mail client with Homebrew. I'm behind a rather terrible proxy with no such thing as FTP proxying. Unfortunately the formula for Alpine requires I retrieve a package from an FTP server.

I can grab the file by other means and get it on my local system, but I need to know how to tell Homebrew to use the specified package instead of trying to download it on its own.

Is this possible?

My usual workaround of running brew install inside of tsocks fails for some inadequately defined reason (just fails to connect exactly as if I hadn't tried it.. yet I can wget the file with tsocks just fine.
After some digging, I stumbled upon the fact that you can find the exact filename that Homebrew is looking for, download the file, and place it file into /Library/Caches/Homebrew, and try the install again. brew will then notice that the file has already been downloaded and continue following the recipe.