Here a short cheat sheet of common commands I use with git/github:
#To stage any modified file, including deleted ones.
git add -u
#stage all new files
git add .
#or
git add --all
# Commit any local change in tracked files
git commit -a -m 'message'
#Reverse a commit
git commit --ammend
#checkout branch and create it if doesn't exists
git checkout -b 2.0 origin/2.0
#To ignore changes in a file, perfect for config files
git update-index --assume-unchanged FILENAME
#git ignore example .gitignore
oc/cache/*
oc/logs/*
images/*