Work with Git

git new repository
git init .

This will create a new commint into git
option -m adds msg

Create merge/pull request
git add .
git status
git commit -m "Added photo of kittens to the theme header per client request."
git push

undo all changes since last save/commint
git reset --hard HEAD

go back one further
git revert HEAD^.

restore a particular file
git checkout -- path/to/filename.php

shows you your current work
git status

show list of you commits
git log --pretty=oneline

show last 5 commits
git log --pretty=oneline -n5

You'll probably want to create a .gitignore file right away, to indicate all of the files you don't want to track.
git add .gitignore

Add a new branch experimantal
git checkout -b experimental

Change to another branch
git checkout experimental

Checkout to remote branch
git checkout -b branchxyz origin/branchxyz

Check files that are being pushed
git diff --stat --cached origin/master

Git rebase
git rebase -i origin/master

Set branch upstream
git branch --set-upstream-to=origin/my_branch_name my_branch_name