git config remote.origin.url https://DoctorWkt@github.com/DoctorWkt/pdp7-unix.git
to cache my Github username

git config --global user.name "Warren Toomey"
git config --global user.email wkt@tuhs.org
git config --global push.default simple

To bring your own local repository up to date with Github:
 git fetch origin 
 git diff master origin/master
 git merge origin/master

To recover a delete file $file:
 git checkout $(git rev-list -n 1 HEAD -- "$file")^ -- "$file"

To see the log of changes to one file
 	git log -- file