how to discard changes in git command line 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 discard changes

git checkout .

Example 3: git delete changes

git clean -df
git checkout -- .

Example 4: how to undo git clean -fd command

git clean -fdx

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