Looking for pre-commit hook to check whitespace errors but not for all files

Dear git folks, in coreboot we try to check for whitespace errors before committing. Of course a pre-commit hook is the way to go, but unfortunately it is not so simple (at least for me) as the following requirements exist. 1. Only the files actually committed should be checked. That means

git log: Add a switch to limit the number of displayed lines from the commit messages

Dear git folks, there are people out there disliking elaborate commit messages, as going over `git log` is tedious as you have to scroll a lot. As I do not like the suggestion to make commit messages shorter by omitting certain details, a way to limit the number displayed lines of the commit