Great pdf cheatsheet for Git commands at https://github.github.com/training-kit/downloads/github-git-cheat-sheet.pdf

Here is a brief summary
Start a new repository or obtain one from an existing URL
$ git init [project-name]
Creates a new local repository with the specified name
$ git clone [url]
Downloads a project and its entire version history

$ git status
Lists all new or modified files to be committed
$ git add [file]
Snapshots the file in preparation for versioning
$ git reset [file]
Unstages the file, but preserve its contents
$ git diff
Shows file differences not yet staged
$ git commit -m “[descriptive message]”
Records file snapshots permanently in the version history

Side note
git add . (with a dot) adds all modified and new (untracked) files in the current directory and all subdirectories to the staging area (a.k.a. the index), thus preparing them to be included in the next git commit.

Any files matching the patterns in the .gitignore file will be ignored by
git add .

$ git log
Lists version history for the current branch

$ git fetch [bookmark]
Downloads all history from the repository bookmark
$ git push [alias] [branch]
Uploads all local branch commits to GitHub
$ git pull
Downloads bookmark history and incorporates changes