Above we used
$ git checkout f22b25e mars.txt
to revert mars.txt to its state after the commit f22b25e. But be careful!
The command checkout has other important functionalities and Git will misunderstand
your intentions if you are not accurate with the typing. For example,
if you forget mars.txt in the previous command.
$ git checkout f22b25e
Note: checking out 'f22b25e'.
You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.
If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:
git checkout -b <new-branch-name
HEAD is now at f22b25e Start notes on Mars as a base
The “detached HEAD” is like “look, but don’t touch” here,
so you shouldn’t make any changes in this state.
After investigating your repo’s past state, reattach your HEAD with git checkout main.