title = Moving through time
cards = checkout commit-auto

[description]

The yellow boxes are frozen points in time, we call them "commits"! You can travel between them using the "checkout" card! (Try it!)

The grey panel below shows your current environment - click on an object to inspect or modify it!

Can you find out what happened here? Then, come back to the latest commit, and fix the problem, using the "commit" card!

[setup]

mkdir room1 room2
echo "A young girl with brown, curly hair." > room1/little_sister
echo "This piggy bank belongs to the big sister.
It contains 10 coins." > room2/piggy_bank
git add .
git commit -m "The beginning"

mv room1/little_sister room2
git add .
git commit -m "Little sister walks over"

echo "Has 10 coins." >> room2/little_sister
echo "This piggy bank belongs to the big sister.
It is empty." > room2/piggy_bank
git add .
git commit -m "Little sister does something"

mv room2/little_sister room1
git add .
git commit -m "Little sister walks back"

git checkout --detach
git branch -d main

[win]

{ git show HEAD:room2/piggy_bank | grep "10 coins"; } && { git show HEAD:room1/little_sister | grep -v "10 coins"; } && { git rev-parse HEAD^; }

[congrats]

Wonderful! Now that you're getting familiar with the time machine, let's look at some more complicated situations...