Reset local repository branch to be just like remote repository HEAD

tl;dr

Step 1 - Save your current work

If you want to save your current branch's state before resetting it, you can do the following:

git commit -a -m "Saving my work, just in case"
git branch my-saved-work

Step 2 - Reset your local repository branch

git fetch origin
git reset --hard origin/master

Note - the commands above assume that the remote repository is named "origin" and that the branch named "master" in the remote repository matches the currently checked-out branch in your local repository.

Note - avoid pushing into a non-bare repository. If you recently pushed into your local repository, you should be aware that it is not recommended to push into a non-bare repository (and not into the currently checked-out branch, in particular).