Some useful git commands which I learned.
If you want to delete everything (.git folder, files and folders), just delete the whole directory:
rm -rf directoryname
Add all file:
git add .
git commit -m "Your commit"
Change last commit:
git commit --amend
Whenever you are doing a git pull, always use the rebasing option:
git pull --rebase
Changing multiple commit message (interactive rebase):
git rebase -i HEAD~number