how to discard staged changes in git code example

Example 1: git discard local changes

# Discarding local changes (permanently) to a file:
git checkout -- <file>

# Discard all local changes to all files permanently:
git reset --hard

Example 2: git undo all changes

git reset --hard

Example 3: revert unstaged changes git

git checkout -- .

Example 4: git discard staged changes

git reset HEAD
git checkout .

Example 5: git discard changes

Undoing the changes in the working directory
Use the checkout command in order to checkout the repository’s version.

RUN:
git checkout hello.html