How to view the committed files you have not pushed yet?

Assuming you're on local branch master, which is tracking origin/master:

git diff --stat origin/master..

Here you'll find your answer:

Using Git how do I find changes between local and remote

For the lazy:

1. Use "git log origin..HEAD"
2. Use "git fetch" followed by "git log HEAD..origin". You can cherry-pick individual commits using the listed commit ids.

The above assumes, of course, that "origin" is the name of your remote tracking branch (which it is if you've used clone with default options).

The push command has a -n/--dry-run option which will compute what needs to be pushed but not actually do it. Does that work for you?