If you just want to see a list of files with changes in the .git repository you are in then just fire terminal up and run the following command.
git diff --name-only
For a more detailed view of all changed files:
For a detailed view of just one file:
git diff application/routes.php
Show all un-committed / un-tracked files
git ls-files --other --exclude-standard
Undo the last commit
git reset --hard HEAD^1
All pretty useful git diff commands.