Referring to the previous/next commit in git?

Question

I have seen git commands use a syntax such as HEAD~, but I haven\'t been able to find this syntax in the Git Reference Manual.

Here is what I have under

Answer 1

To simply answer the question from title (since that's what got me here from Google):

To checkout the previous commit:

git checkout HEAD^

To checkout the next commit (assuming there's no branching):

git checkout `git log --reverse --ancestry-path HEAD..master | head -n 1 | cut -d \  -f 2`