Whenever you do git pull and you find some files modified locally as part of build and want to overwrite it with the contents in the git repository.
git checkout HEAD^ file/to/overwrite
To checkout a new git branch and to create a new git branch and checkout
git checkout <branch>
git checkout -b <branch>
To delete a remote branch and local branch
git push –delete origin bugfix/
git branch -d bugfix/
To copy a directory without its history and add as a new folder in git
cp -R old_dir new_dir
git add new_dir
git commit -m "first revision of new_dir's copied files"