git checkout all the files

If you are at the root of your working directory, you can do git checkout -- . to check-out all files in the current HEAD and replace your local files.

You can also do git reset --hard to reset your working directory and replace all changes (including the index).

Other way which I found useful is:

git checkout <wildcard> 

Example:

git checkout *.html

More generally:

git checkout <branch> <filename/wildcard>