git discard all changes and pull from upstream

Question

There are (at least) two things you can do here–you can reclone the remote repo, or you can reset --hard to the common ancestor and then do a pull, which will fast-forward to the latest commit on the remote master.

To be concrete, here's a simple extension of Nevik Rehnel's original answer:

git reset --hard origin/master
git pull origin master

NOTE: using git reset --hard will discard any uncommitted changes, and it can be easy to confuse yourself with this command if you're new to git, so make sure you have a sense of what it is going to do before proceeding.

while on branch master: git reset --hard origin/master

then do some clean up with git gc (more about this in the man pages)

Update: You will also probably need to do a git fetch origin (or git fetch origin master if you only want that branch); it should not matter if you do this before or after the reset. (Thanks @eric-walker)

You can do it in a single command:

git fetch --all && git reset --hard origin/master

Or in a pair of commands:

git fetch --all
git reset --hard origin/master

Note than you will lose ALL your local changes

git reset <hash>  # you need to know the last good hash, so you can remove all your local commits

git fetch upstream
git checkout master
git merge upstream/master
git push origin master -f

voila, now your fork is back to same as upstream.

I finally realized now that instead of

git fetch --all && git reset --hard origin/master

it should be

git fetch --all && git reset --hard origin/<branch_name>

instead (if one works on a different branch)