Pre-Commit hooks and Code Format checkers.

Hi all,
    I want to know if it's possible to insert a pre-commit hook that can
check the incoming code against a formatter. My company actually wants to
set it up to automatically format any code that comes in before it gets
committed, but I know that the pre-commit hook isn't supposed to change the
actual commit. From my understanding it's supposed to be more of a pass/fail
check. If the commit is "valid" (for however many reasons) then the commit
is allowed, otherwise it is denied.

Is this possible?

Thanks in advance for any help.
Eric

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