Undoing Changes
The main purpose of our version control system is to store versions of files, to have the ability to review these versions, and to revert to any version.
First, I review the log, one line at a time.

I want to revert to the previous committed version, I use the command
git revert HEAD
Visual Studio Code pops up so I can add a message. I click the tick symbol.

A quick review of the file demonstrates that I have reverted.
There are many functions which we can use to undo changes, I'm not going to go into them here.