Linux Terminal: Where Am I? A Folder Treasure Hunt

Before you start: try it once yourself

Do the hunt yourself once before you start. It takes about ten minutes, and you will know exactly what your child will see.

1. Open the lesson. Go to mytekdev.com/try/terminal?lesson=where-am-i&ref=fam-terminal-1. The terminal prints Lesson ready: Where Am I?
2. Look around. Type ls: the hunt's games/ and school/ sit beside the folders every account has (apps/, projects/, public_html/, shared/), with start-here.txt. Type cat start-here.txt and read it.
3. Clue 1. cd school/science/labs, then pwd: it prints /home/ and a guest name, then /school/science/labs. cat clue.txt.
4. Clue 2. cd ../../art, then cat clue.txt.
5. Clue 3. Type cd /home/, your own guest name from pwd, then /games/saves. cat clue.txt.
6. The treasure. cd ~, then ls -a: .treasure.txt appears. cat .treasure.txt gives the code word LANTERN.
7. The map. apt install tree, wait a few seconds, then tree. The last line says 8 directories, 8 files.

What the tree shows at the end.

The ideas, in plain words

A terminal is a way to use a computer by typing commands instead of clicking. Each command is a word, sometimes followed by options that start with a dash and by the names of files. The computer runs it and prints an answer, or prints nothing when it worked. The terminal in this lesson is a real Linux-style shell running on our server; each visitor gets a fresh guest one, and nothing they type can reach anyone else's files.

Files live in a tree of folders. The top of the tree is / (called root). Each guest has a home folder, /home/ and their guest name, which ~ stands for. A path is the directions down the tree: school/science/labs means labs, inside science, inside school. A relative path starts from the folder you are in; an absolute path starts at / and works from anywhere. .. means the folder above. A file whose name starts with a dot is hidden: ls skips it and ls -a shows it.

Do it together

1. Start with a question: your computer has thousands of files, so when you double-click a folder, how does the computer know which one you mean? Then open mytekdev.com/try/terminal?lesson=where-am-i&ref=fam-terminal-1 together.

   You'll know it worked when: The terminal prints Lesson ready: Where Am I?. The hunt is already set up in the folders.

2. Type pwd and press Enter: it prints the folder you are in, your home folder. Then type ls: it lists what is in this folder, with a / after each folder's name.

   You'll know it worked when: pwd prints /home/ and a guest name ending in a number, which is different every time. ls shows games/ and school/ beside apps/, projects/, public_html/ and shared/, and a file called start-here.txt.

3. Type cat start-here.txt and read it together. Learn the three moves: cd and a folder name goes down into it, cd .. goes up one, and cd ~ (or just cd) goes home from anywhere. A command that worked often prints nothing at all.

   You'll know it worked when: Your child can say the three moves, or point to them at the top of the activity sheet.

4. Clue 1: type cd school/science/labs, then pwd, then cat clue.txt. Write down what pwd says. That path goes three folders down from home: labs, inside science, inside school.

   If you get stuck: No such file or directory after a cd means a typo or a missing slash. ls shows the folder names exactly as they are spelled.

   You'll know it worked when: pwd ends in /school/science/labs, and the clue is on the screen.

5. The clue on the screen says to go up two folders and into art in one step: cd ../../art, then pwd and cat clue.txt. Ask why it takes two .. and not one.

   You'll know it worked when: Your child explains that art is not inside labs: each .. goes up one folder, labs to science, science to school, and school has art in it.

6. The next clue needs an absolute path, the whole path from the top: type cd /home/, then the guest name from pwd, then /games/saves, all as one command. Then cat clue.txt.

   You'll know it worked when: pwd says /home/, the guest name, then /games/saves. Your child can say the difference: an absolute path starts at / and works from anywhere.

7. The treasure is hidden at home. Type cd ~, then ls: nothing new. Then ls -a, and cat the file that appears.

   If you get stuck: A plain ls never shows it: the file's name starts with a dot, which hides it, so only ls -a lists it.

   You'll know it worked when: ls -a shows .treasure.txt, and cat .treasure.txt gives the code word LANTERN.

8. Draw the map: type apt install tree, wait for the prompt to come back, then type tree. Ask where the tree command came from: the terminal itself is system software, and apt added a small application on top of it.

   If you get stuck: A command typed while tree is still installing can lose letters, so wait for the prompt. If the files get into a mess, typing lesson start where-am-i puts them back. Reloading the page starts a new, empty terminal; the lesson link sets the files up again.

   You'll know it worked when: tree draws every folder of the hunt and ends with 8 directories, 8 files.

9. Talk it over: why does a computer keep files in a tree of folders instead of one long list?

   You'll know it worked when: Your child names a reason or two: it is easier to find things, related files stay together, and two files with the same name can live in different folders.

10. The real question, without trying it first: you are in school/science/labs. What one command takes you to school/math? Then try it.

    You'll know it worked when: Your child answers cd ../../math, reasoning up to school and back down, without a clue to copy. That means they can picture the tree.

Talk about it

Ask these while you work together. A child who has understood the lesson can answer them without help:

• Where are you right now? How do you know?
• Why does cd ../../art need two .. and not one?
• What would happen if you typed cd ../../art from a different folder? Why does the clue in art ask for an absolute path?
• Why didn't plain ls show the treasure?
• Without trying it: you are in school/science/labs. What one command takes you to school/math?

Bring it into other subjects

• Math: a folder tree is a tree diagram, like a probability tree or a family tree. Draw the hunt's tree by hand, then compare with tree.
• Social studies: a library shelves books by a path too (floor, section, shelf). Write directions to a book as a path.
• Language arts: write the instructions for a treasure hunt in your home as a set of relative directions.
• Computer science: the same terminal can make, move and delete files.

Quick check

Name: ______________________________

1. You are in /home/sam/school/art. Where does cd .. take you? (A) /home/sam, (B) /home/sam/school, (C) /.

2. Which command shows hidden files? (A) ls, (B) ls -a, (C) cat.

3. Is /home/sam/games an absolute or a relative path? How can you tell, and why would you use it?

Answers

From the guest terminal with the hunt set up. Every guest's home folder is /home/ plus their guest username (for example /home/guest10), so the pwd column shows that guest's own name.

The code word is LANTERN. tree then shows 8 directories and 8 files. Relative example: school/science/labs. Absolute example: /home/(username)/games/saves.