git

Reset file to HEAD

To reset both the working copy of my-file.txt and its state in the Git index to that of HEAD:

git checkout HEAD -- my-file.txt

Remove last commit

… without deleting the changes.

git reset --soft HEAD~1

Update forked repository

# Add the remote, call it "upstream":

git remote add upstream https://github.com/whoever/whatever.git

# Fetch all the branches of that remote into remote-tracking branches,
# such as upstream/master:

git fetch upstream

# Make sure that you're on your master branch:

git checkout master

# Rewrite your master branch so that any commits of yours that
# aren't already in upstream/master are replayed on top of that
# other branch:

git rebase upstream/master