Viewing unpushed Git commits

git log origin/master..HEAD

You can also view the diff using the same syntax

git diff origin/master..HEAD

If you want to see all commits on all branches that aren't pushed yet, you might be looking for something like this:

git log --branches --not --remotes

And if you only want to see the most recent commit on each branch, and the branch names, this:

git log --branches --not --remotes --simplify-by-decoration --decorate --oneline

You can show all commits that you have locally but not upstream with

git log @{u}..

@{u} or @{upstream} means the upstream branch of the current branch (see git rev-parse --help or git help revisions for details).