undo git change on file code example

Example 1: git remove my local changes and pull from master

git reset --hard <your commit hash key>

Example 2: git abort changes

git stash save --keep-index --include-untracked
You don't need to include --include-untracked if you don't want to be thorough about it.

After that, you can drop that stash with a git stash drop command if you like.