Here is my little cheat sheet for working with git at the command line.
Check the status of the current repository:
git status
This will return details of which files are modified and any files that are untracked, etc.
Add a file to the repository:
git add <filename>
You can also replace filename with a dot (.) to include all untracked files. Use git status before to find out what files are currently untracked.
Commit the changes to the local repository:
git commit -m "<commit message>"
This will only commit the changes as far as the local repository.
Send the changes back to the server:
git push origin master
origin is the name of the remote location of the repository. It is more-or-less, by convention, where you cloned your local repository from.
master is the name of the branch. By convention this is your default branch.
Revert a file to the version at the previous commit:
git checkout -f <filename>
Delete files from the repository
git rm <filename>
If you want to delete an entire directory you need to add the -r (recursive) flag.
git rm -r <folder-path>
You may also need to choose between keeping the files on the disk and removing them altogether. In which case you want either --cached, to remove them from the repository but keep them on disk, or -f to force the removal of the file from disk.
The Blog of Colin Mackay 