feat: add English translations for quests

quests/checkpoint-01/en/answer.sh

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+echo start
+echo next
+ls
+cd folder03
+pwd
+cd ../folder02
+ls ../folder01

quests/checkpoint-01/en/game.yml

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+id: checkpoint-01
+title: Checkpoint 1
+image: base
+instruction: |
+  This quest tests your understanding of:
+  1. `echo`: print text
+  2. `ls`: list the contents of a folder
+  3. `cd`: move between folders
+  4. `pwd`: show your current path
+
+requirements:
+  - path
+
+stages:
+  - id: start
+    name: Click `Start` to begin
+    condition:
+      command: echo start
+    response:
+      content: |
+        This quest checks what you have learned in the previous lessons.
+        You will need to choose the commands yourself.
+        Think about which commands can help you complete each task.
+
+        To continue, make the terminal print `next`.
+
+  - id: next
+    name: Make the terminal print `next`
+    requirements:
+      - start
+    condition:
+      output: next
+    response:
+      content: |
+        Now list the contents of your current folder.
+
+  - id: ls-home
+    name: List the contents of the current folder
+    requirements:
+      - next
+    condition:
+      pwd: /home/commander
+      command: ls
+    response:
+      content: |
+        Enter the `folder03` folder.
+
+  - id: cd-folder03
+    name: Enter `folder03`
+    requirements:
+      - ls-home
+    condition:
+      pwd: /home/commander/folder03
+    response:
+      content: |
+        Show your current path in the terminal.
+
+  - id: pwd-folder03
+    name: Show your current path
+    requirements:
+      - cd-folder03
+    condition:
+      command: pwd
+      output: /home/commander/folder03
+    response:
+      content: |
+        Now enter the `folder02` folder
+        and list its contents.
+
+  - id: ls-folder02
+    name: Enter `folder02` and list its contents
+    requirements:
+      - pwd-folder03
+    condition:
+      pwd: /home/commander/folder02
+      command: ls
+    response:
+      content: |
+        Finally, stay in `folder02`
+        and list the contents of `folder01`.
+
+  - id: finish
+    name: Stay in `folder02` and list the contents of `folder01`
+    requirements:
+      - ls-folder02
+    condition:
+      pwd: /home/commander/folder02
+      output: file1.txt
+    response:
+      content: |
+        Congratulations! You passed this checkpoint!
+        You are ready to move on to the next lessons.

quests/checkpoint-02/en/answer.sh

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+echo start
+echo next
+ls
+cat hello.txt
+cat pneumonoultramicroscopicsilicovolcanoconiosis.txt
+mkdir folder
+touch folder/file.txt

quests/checkpoint-02/en/game.yml

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+id: checkpoint-02
+title: Checkpoint 2
+image: base
+instruction: |
+  This quest tests your understanding of:
+  1. `cat`: display the contents of a file
+  2. `touch`: create a file
+  3. `mkdir`: create a folder
+  4. Use the `Tab` key for autocompletion
+  5. Topics covered in the previous checkpoint
+
+requirements:
+  - create
+
+stages:
+  - id: start
+    name: Click `Start` to begin
+    condition:
+      command: echo start
+    response:
+      content: |
+        This quest checks what you have learned in the previous lessons.
+        You will need to choose the commands yourself.
+        Think about which commands can help you complete each task.
+
+        To continue, make the terminal print `next`.
+
+  - id: next
+    name: Make the terminal print `next`
+    requirements:
+      - start
+    condition:
+      output: next
+    response:
+      content: |
+        Now list the contents of your current folder.
+
+  - id: ls-home
+    name: List the contents of the current folder
+    requirements:
+      - next
+    condition:
+      pwd: /home/commander
+      command: ls
+    response:
+      content: |
+        Display the contents of `hello.txt`.
+
+  - id: cat-hello
+    name: Display the contents of `hello.txt`
+    requirements:
+      - ls-home
+    condition:
+      command: cat hello.txt
+      output: This is `hello.txt`.
+    response:
+      content: |
+        Display the contents of the other file, which has a very long name.
+
+  - id: cat-long-filename
+    name: Display the contents of the other file
+    requirements:
+      - cat-hello
+    condition:
+      command: cat pneumonoultramicroscopicsilicovolcanoconiosis.txt
+      output: A name that has been invented for a lung disease caused by breathing in very small pieces of ash or dust.
+    response:
+      content: |
+        Now create a folder named `folder`.
+
+  - id: mkdir-folder
+    name: Create a folder named `folder`
+    requirements:
+      - cat-long-filename
+    condition:
+      files:
+        - path: /home/commander/folder
+          type: directory
+          exists: true
+    response:
+      content: |
+        Finally, inside the `folder` folder,
+        create a file named `file.txt`.
+
+  - id: finish
+    name: Create `file.txt` inside `folder`
+    requirements:
+      - mkdir-folder
+    condition:
+      files:
+        - path: /home/commander/folder/file.txt
+          type: file
+          exists: true
+    response:
+      content: |
+        Congratulations! You passed this checkpoint!
+        You are ready to move on to the next lessons.

quests/checkpoint-02/en/home/hello.txt

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+This is `hello.txt`.

quests/checkpoint-02/en/home/pneumonoultramicroscopicsilicovolcanoconiosis.txt

@@ -0,0 +1 @@
+A name that has been invented for a lung disease caused by breathing in very small pieces of ash or dust.

quests/checkpoint-03/en/answer.sh

@@ -0,0 +1,12 @@
+echo start
+echo next
+ls
+cd folder
+cp hello.txt world.txt
+rm hello.txt
+mv world.txt ..
+cd ..
+mv world.txt hello.txt
+cat hello.txt
+rmdir folder
+rm -r trash_can

quests/checkpoint-03/en/game.yml

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+id: checkpoint-03
+title: Checkpoint 3
+image: base
+instruction: |
+  This quest tests your understanding of:
+  1. `cp`: copy files and folders
+  2. `mv`: move or rename files and folders
+  3. `rm`: delete files and folders
+  4. `rmdir`: delete empty folders
+  5. Use options to change a command's behavior, such as `rm -r`
+  6. Topics covered in the previous checkpoints
+
+requirements:
+  - remove
+
+stages:
+  - id: start
+    name: Click `Start` to begin
+    condition:
+      command: echo start
+    response:
+      content: |
+        This quest checks what you have learned in the previous lessons.
+        You will need to choose the commands yourself.
+        Think about which commands can help you complete each task.
+
+        To continue, make the terminal print `next`.
+
+  - id: next
+    name: Make the terminal print `next`
+    requirements:
+      - start
+    condition:
+      output: next
+    response:
+      content: |
+        Now list the contents of your current folder.
+
+  - id: ls-home
+    name: List the contents of the current folder
+    requirements:
+      - next
+    condition:
+      pwd: /home/commander
+      command: ls
+    response:
+      content: |
+        Copy the file inside `folder` to a new file named `world.txt` in the same folder.
+
+  - id: cp-hello-world
+    name: Copy the file inside `folder` as `world.txt`
+    requirements:
+      - ls-home
+    condition:
+      files:
+        - path: /home/commander/folder/hello.txt
+          type: file
+          exists: true
+        - path: /home/commander/folder/world.txt
+          type: file
+          exists: true
+    response:
+      content: |
+        Delete the `hello.txt` file inside `folder`.
+
+  - id: rm-hello
+    name: Delete `hello.txt` inside `folder`
+    requirements:
+      - cp-hello-world
+    condition:
+      files:
+        - path: /home/commander/folder/hello.txt
+          type: file
+          exists: false
+    response:
+      content: |
+        Now move `world.txt` out of `folder`.
+        (Move it into your home folder, `/home/commander`.)
+
+  - id: mv-world-out
+    name: Move `world.txt` out of `folder`
+    requirements:
+      - rm-hello
+    condition:
+      files:
+        - path: /home/commander/folder/world.txt
+          type: file
+          exists: false
+        - path: /home/commander/world.txt
+          type: file
+          exists: true
+    response:
+      content: |
+        Rename `world.txt` back to `hello.txt`
+        and display its contents.
+
+  - id: cat-hello
+    name: Rename `world.txt` to `hello.txt` and display its contents
+    requirements:
+      - mv-world-out
+    condition:
+      command: cat hello.txt
+      files:
+        - path: /home/commander/world.txt
+          type: file
+          exists: false
+        - path: /home/commander/hello.txt
+          type: file
+          exists: true
+      output: This is `hello.txt`.
+    response:
+      content: |
+        Delete the `folder` folder.
+
+  - id: rmdir-folder
+    name: Delete `folder`
+    requirements:
+      - cat-hello
+    condition:
+      files:
+        - path: /home/commander/folder
+          type: directory
+          exists: false
+    response:
+      content: |
+        Delete the `trash_can` folder.
+
+  - id: finish
+    name: Delete `trash_can`
+    requirements:
+      - rmdir-folder
+    condition:
+      files:
+        - path: /home/commander/trash_can
+          type: directory
+          exists: false
+    response:
+      content: |
+        Congratulations! You passed this checkpoint!
+        You are ready to move on to the next lessons.

quests/checkpoint-03/en/home/folder/hello.txt

@@ -0,0 +1 @@
+This is `hello.txt`.

quests/checkpoint-03/en/home/trash_can/secret/letter.txt

@@ -0,0 +1 @@
+aHR0cHM6Ly9yZXVybC5jYy9YUjZZMDA=

quests/copy/en/answer.sh

@@ -0,0 +1,13 @@
+echo start
+ls
+cat hello.txt
+cat world.txt
+echo next
+cp hello.txt hello2.txt
+cat hello2.txt
+cp world.txt world2.txt
+cat world2.txt
+cp -r notes notes2
+ls notes2
+cp hello.txt world.txt
+cat world.txt

quests/copy/en/game.yml

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+id: copy
+title: Copying Files
+image: base
+instruction: |
+  In this quest, you will learn:
+  1. How to copy files with `cp`
+
+requirements:
+  - create
+
+stages:
+  - id: start
+    name: Click `Start` to begin
+    condition:
+      command: echo start
+    response:
+      content: |
+        Today we will learn how to copy files.
+        First, use `ls` to see which files are in your current folder.
+      hint: Use `ls` to list the files in your current folder
+
+  - id: ls
+    name: List the files in the current folder
+    requirements:
+      - start
+    condition:
+      pwd: /home/commander
+      command: ls
+    exceptions:
+      - id: wrong_directory
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          content: |
+            You are outside the `/home/commander` folder.
+            Use `cd /home/commander` to return to `/home/commander`.
+    response:
+      content: |
+        You can see `hello.txt` and `world.txt` in this folder.
+        Use `cat` to display their contents.
+        When you have finished, enter `echo next` to continue!
+      hint: |
+        Use `cat hello.txt` and `cat world.txt` to display the file contents
+        If a command is keeping the terminal busy, press `Ctrl + C` to cancel it
+
+  - id: cat-hello
+    name: Display the contents of `hello.txt`
+    requirements:
+      - ls
+    condition:
+      pwd: /home/commander
+      command: cat hello.txt
+      output: Hello
+    exceptions:
+      - id: wrong_directory
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          content: |
+            You are outside the `/home/commander` folder.
+            Use `cd /home/commander` to return to `/home/commander`
+      - id: missing_command
+        condition:
+          command: cat
+        response:
+          content: |
+            To display this file, add its filename after `cat`.
+            If `cat` is waiting for input, press `Ctrl + C` to cancel it.
+            Enter `cat hello.txt` to display the contents of `hello.txt`
+      - id: missing_extension
+        condition:
+          command: cat hello
+        response:
+          content: |
+            Did you forget the `.txt` extension?
+            Enter `cat hello.txt` to display the contents of `hello.txt`
+    response:
+      content: |
+        You have displayed the contents of `hello.txt`!
+        Here is what it contains:
+        ```
+        Hello
+        ```
+
+  - id: cat-world
+    name: Display the contents of `world.txt`
+    requirements:
+      - ls
+    condition:
+      pwd: /home/commander
+      command: cat world.txt
+      output: World
+    exceptions:
+      - id: wrong_directory
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          content: |
+            You are outside the `/home/commander` folder.
+            Use `cd /home/commander` to return to `/home/commander`
+      - id: missing_command
+        condition:
+          command: cat
+        response:
+          content: |
+            To display this file, add its filename after `cat`.
+            If `cat` is waiting for input, press `Ctrl + C` to cancel it.
+            Enter `cat world.txt` to display the contents of `world.txt`
+      - id: missing_extension
+        condition:
+          command: cat world
+        response:
+          content: |
+            Did you forget the `.txt` extension?
+            Enter `cat world.txt` to display the contents of `world.txt`
+    response:
+      content: |
+        You have displayed the contents of `world.txt`!
+        Here is what it contains:
+        ```
+        World
+        ```
+
+  - id: cat-next
+    name: Enter `echo next` to continue
+    requirements:
+      - cat-hello
+      - cat-world
+    condition:
+      command: echo next
+    response:
+      content: |
+        Next, let's learn how to copy files.
+        `cp` is short for copy.
+        To copy a file, use `cp [source file] [destination file]`.
+        Use `cp` to copy `hello.txt` to `hello2.txt`.
+      hint: Use `cp hello.txt hello2.txt` to copy `hello.txt` to `hello2.txt`
+
+  - id: cp-hello
+    name: Copy `hello.txt` to `hello2.txt`
+    requirements:
+      - cat-next
+    condition:
+      pwd: /home/commander
+      command: cp hello.txt hello2.txt
+      files:
+        - path: /home/commander/hello2.txt
+          type: file
+          exists: true
+    exceptions:
+      - id: wrong_directory
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          content: |
+            You are outside the `/home/commander` folder.
+            Use `cd /home/commander` to return to `/home/commander`.
+    response:
+      content: |
+        You have copied `hello.txt` to `hello2.txt`!
+        Let's check the contents of `hello2.txt`.
+      hint: Use `cat hello2.txt` to display the contents of `hello2.txt`
+
+  - id: cat-hello2
+    name: Display the contents of `hello2.txt`
+    requirements:
+      - cp-hello
+    condition:
+      pwd: /home/commander
+      command: cat hello2.txt
+      output: Hello
+    exceptions:
+      - id: wrong_directory
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          content: |
+            You are outside the `/home/commander` folder.
+            Use `cd /home/commander` to return to `/home/commander`.
+    response:
+      content: |
+        You have displayed the contents of `hello2.txt`!
+        As you can see, `hello2.txt` contains exactly the same text as `hello.txt`.
+        Now try copying `world.txt` to `world2.txt`!
+      hint: Use `cp world.txt world2.txt` to copy `world.txt` to `world2.txt`
+
+  - id: cp-world
+    name: Copy `world.txt` to `world2.txt`
+    requirements:
+      - cat-hello2
+    condition:
+      pwd: /home/commander
+      command: cp world.txt world2.txt
+      files:
+        - path: /home/commander/world2.txt
+          type: file
+          exists: true
+    exceptions:
+      - id: wrong_directory
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          content: |
+            You are outside the `/home/commander` folder.
+            Use `cd /home/commander` to return to `/home/commander`.
+    response:
+      content: |
+        You have copied `world.txt` to `world2.txt`!
+        Let's check the contents of `world2.txt`.
+      hint: Use `cat world2.txt` to display the contents of `world2.txt`
+
+  - id: cat-world2
+    name: Display the contents of `world2.txt`
+    requirements:
+      - cp-world
+    condition:
+      pwd: /home/commander
+      command: cat world2.txt
+      output: World
+    exceptions:
+      - id: wrong_directory
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          content: |
+            You are outside the `/home/commander` folder.
+            Use `cd /home/commander` to return to `/home/commander`.
+    response:
+      content: |
+        You have displayed the contents of `world2.txt`!
+        `world2.txt` contains exactly the same text as `world.txt`.
+        Next, let's learn how to copy folders.
+        Your current folder contains a `notes` folder with a file named `note.txt` inside.
+        We want to copy the entire folder, including its contents, to `notes2`.
+        To copy a folder, add the `-r` option (recursive). This copies the folder and everything inside it.
+        Options let you change how a command behaves.
+        An option often starts with `-` followed by a letter, such as `-r`.
+        Options usually go after the command name and before the filenames.
+        Use `cp -r notes notes2` to copy `notes` to `notes2`.
+      hint: |
+        Use `cp -r notes notes2` to copy `notes` to `notes2`
+        Remember to include `-r` to copy all the contents
+
+  - id: cp-notes
+    name: Copy the `notes` folder to `notes2`
+    requirements:
+      - cat-world2
+    condition:
+      pwd: /home/commander
+      command: cp -r notes notes2
+      files:
+        - path: /home/commander/notes2
+          type: directory
+          exists: true
+        - path: /home/commander/notes2/note.txt
+          type: file
+          exists: true
+    exceptions:
+      - id: wrong_directory
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          content: |
+            You are outside the `/home/commander` folder.
+            Use `cd /home/commander` to return to `/home/commander`.
+      - id: missing_recursive
+        condition:
+          command: cp notes notes2
+        response:
+          content: |
+            Did you forget the `-r` option?
+            Enter `cp -r notes notes2` to copy `notes` to `notes2`
+    response:
+      content: |
+        You have copied the `notes` folder to `notes2`!
+        The entire `notes` folder, including its files, has been copied to `notes2`.
+        `cp -r` copies everything in a folder, including files inside any nested folders.
+
+        Finally, let's see what happens when you copy a file to a destination that already exists.
+        Copy `hello.txt` to `world.txt` and see what happens.
+      hint: Use `cp hello.txt world.txt` to copy `hello.txt` to `world.txt`
+
+  - id: cp-overwrite
+    name: Copy `hello.txt` to `world.txt`
+    requirements:
+      - cp-notes
+    condition:
+      pwd: /home/commander
+      command: cp hello.txt world.txt
+    exceptions:
+      - id: wrong_directory
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          content: |
+            You are outside the `/home/commander` folder.
+            Use `cd /home/commander` to return to `/home/commander`.
+    response:
+      content: |
+        You have copied `hello.txt` to `world.txt`!
+        Let's check the contents of `world.txt`.
+      hint: Use `cat world.txt`
+
+  - id: check-world
+    name: Check the contents of `world.txt`
+    requirements:
+      - cp-overwrite
+    condition:
+      pwd: /home/commander
+      command: cat world.txt
+      output: Hello
+    exceptions:
+      - id: wrong_directory
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          content: |
+            You are outside the `/home/commander` folder.
+            Use `cd /home/commander` to return to `/home/commander`.
+    response:
+      content: |
+        `world.txt` now contains `Hello`!
+        When the destination file already exists, copying another file to it overwrites its contents.
+        Check whether the destination already exists before copying, so you do not accidentally lose data.
+        That covers the basics of copying files!
+        Enter `echo finish` to complete this quest.
+
+  - id: finish
+    name: Congratulations! All tasks completed!
+    requirements:
+      - check-world
+    condition:
+      command: echo finish
+    response:
+      content: |
+        Congratulations! You have completed all the tasks!
+        You now know how to copy files and folders.
+        In the next quest, you will learn how to move files and folders.

quests/copy/en/home/hello.txt

@@ -0,0 +1 @@
+Hello

quests/copy/en/home/notes/note.txt

@@ -0,0 +1 @@
+Note

quests/copy/en/home/world.txt

@@ -0,0 +1 @@
+World

quests/create/en/answer.sh

@@ -0,0 +1,12 @@
+echo start
+ls
+touch hello.txt
+ls
+cat hello.txt
+touch world.txt
+ls
+mkdir notes
+ls
+cd notes
+touch note.txt
+ls

quests/create/en/game.yml

@@ -0,0 +1,165 @@
+id: create
+title: Creating Files and Folders
+image: base
+instruction: |
+  In this quest, you will learn:
+  1. How to create files with `touch`
+  2. How to create folders with `mkdir`
+
+requirements:
+  - tab
+
+stages:
+  - id: start
+    name: Click `Start` to begin
+    condition:
+      command: echo start
+    response:
+      content: |
+        This time, we will learn about the `touch` command.
+        First, use `ls` to list the files in your current folder.
+        You should find that the folder has no files.
+      hint: Enter `ls` to list the files in your current folder
+
+  - id: ls
+    name: List the files in the folder
+    requirements:
+      - start
+    condition:
+      command: ls
+    response:
+      content: |
+        The terminal shows no output, which means there are no visible files in this folder.
+        You can create a file with `touch [filename]`.
+        Try creating a file named `hello.txt` in the terminal.
+      hint: Enter `touch hello.txt` to create a file
+
+  - id: touch
+    name: Create a file with `touch`
+    requirements:
+      - ls
+    condition:
+      files:
+        - path: /home/commander/hello.txt
+          type: file
+          exists: true
+    exceptions:
+      - id: missing_extension
+        condition:
+          files:
+            - path: /home/commander/hello
+              type: file
+              exists: true
+        response:
+          content: |
+            It looks like you forgot the `.txt` extension.
+            Try again and make sure the filename is `hello.txt`.
+    response:
+      content: |
+        The terminal should show no output.
+        The file tree on the right now shows the new `hello.txt` file.
+        Let's look inside `hello.txt`!
+        Use the `cat` command you learned earlier to display its contents.
+      hint: Enter `cat hello.txt` to display the contents of `hello.txt`
+
+  - id: cat
+    name: Display the contents of `hello.txt` with `cat`
+    requirements:
+      - touch
+    condition:
+      command: cat hello.txt
+    response:
+      content: |
+        Huh? There is nothing there!
+        That's right. A new file created with `touch` is empty.
+        We will learn how to edit file contents in a future lesson.
+        Let's create another file!
+        Try creating another file named `world.txt` in the terminal.
+      hint: Enter `touch world.txt` to create a file
+
+  - id: touch-2
+    name: Create another file named `world.txt` with `touch`
+    requirements:
+      - cat
+    condition:
+      files:
+        - path: /home/commander/world.txt
+          type: file
+          exists: true
+    exceptions:
+      - id: missing_extension
+        condition:
+          files:
+            - path: /home/commander/world
+              type: file
+              exists: true
+        response:
+          content: |
+            It looks like you forgot the `.txt` extension.
+            Try again and make sure the filename is `world.txt`.
+    response:
+      content: |
+        Great! You have created your second file.
+        The file tree now shows both `hello.txt` and `world.txt`.
+        Next, let's create a folder!
+        The `mkdir` command creates an empty folder.
+        Use `mkdir [folder name]`.
+        Try creating a folder named `notes` in the terminal.
+      hint: Enter `mkdir notes` to create a folder
+
+  - id: mkdir
+    name: Create the `notes` folder with `mkdir`
+    requirements:
+      - touch-2
+    condition:
+      files:
+        - path: /home/commander/notes
+          type: directory
+          exists: true
+    response:
+      content: |
+        Great! You have created the `notes` folder.
+        Next, we will create a file named `note.txt` inside `notes`.
+        First, enter the `notes` folder.
+        Remember the `cd` command? Try using it to enter `notes`.
+      hint: |
+        Enter `cd notes` to enter the `notes` folder
+        After typing `cd n`, press `Tab` to complete the folder name
+
+  - id: cd-notes
+    name: Enter the `notes` folder
+    requirements:
+      - mkdir
+    condition:
+      pwd: /home/commander/notes
+    response:
+      content: |
+        You have entered the `notes` folder.
+        Now try creating a file named `note.txt` inside `notes`.
+      hint: Enter `touch note.txt` to create a file
+
+  - id: touch-note
+    name: Create `note.txt` inside `notes`
+    requirements:
+      - cd-notes
+    condition:
+      files:
+        - path: /home/commander/notes/note.txt
+          type: file
+          exists: true
+    response:
+      content: |
+        Great! You have created `note.txt`.
+        Congratulations! You have completed this quest!
+        In the next quest, you will learn how to copy files and folders.
+        Enter `echo finish` to complete this quest.
+
+  - id: END
+    name: Complete the quest
+    requirements:
+      - touch-note
+    condition:
+      command: echo finish
+    response:
+      content: |
+        Congratulations! You have completed this quest!

quests/execute/en/execute.md

@@ -0,0 +1,79 @@
+# Running Executable Files
+
+## Outline
+
+1. What an executable file is
+2. How to find an executable with `which`
+3. How to run an executable file
+
+---
+
+In earlier lessons, you used commands such as `ls`, `cat`, `cp`, `mv`, and `rm`.
+These commands are **executable files** that the operating system runs when you enter them.
+For most commands, you can find the corresponding file in the file system.
+Use `which` to find the file associated with a command.
+Enter `which [command name]` to display its path.
+
+> Use `which ls` to find the path to `ls`
+
+---
+
+The terminal displays `/usr/bin/ls`, the location of the `ls` executable.
+`/usr/bin` is a system folder containing many standard programs, including commands such as `cat` and `cp`.
+
+> Use `which cat` to find the path to `cat`
+
+---
+
+To run an executable file, enter its path directly.
+Let's try running a command using the path to its executable.
+
+> Enter `/usr/bin/ls` to list the contents of your current folder
+
+---
+
+It lists the files in your folder, just as entering `ls` does. You can compare the results yourself.
+You can still pass arguments. Let's try this with `cat`.
+
+> Enter `/usr/bin/cat hello.txt` to display the contents of `hello.txt`
+
+---
+
+You can see the contents of `hello.txt`, just as you would with `cat`.
+This makes sense: `cat` is located at `/usr/bin/cat`, so both commands run the same program.
+A command like this consists of **an executable** plus **arguments**.
+You can enter `ls` instead of `/usr/bin/ls` because the `PATH` environment variable tells the terminal which *folders* to search for programs.
+`PATH` and environment variables are beyond this lesson's scope. We will cover them in a future lesson.
+
+You can also run custom programs, such as the `dog` file in your current folder.
+
+> Use `cat dog` to display the contents of `dog`
+
+---
+
+This is a simple program built from `echo` and `sleep` commands.
+You do not need to understand every detail yet. It prints a few lines of text, with short pauses between them.
+
+To run a file, specify its path.
+Since `dog` is in your home folder, its absolute path is `/home/commander/dog`. You can also use the shorter form `~/dog`.
+
+> Enter `~/dog` to run the `dog` file
+
+---
+
+The terminal displays a few words from this dog with an attitude.
+When you are in the same folder as a program, a relative path is often more convenient than an absolute path.
+To run a program in your current folder, put `./` before its filename instead of entering just its name.
+In a path, `.` means the current folder.
+Now try running `dog` using a relative path.
+
+> Enter `./dog` to run the `dog` file
+
+---
+
+The dog produces the same output as before.
+This is an example of a simple custom command.
+You can put a sequence of commands in a file and run them together to handle complex or repetitive tasks.
+This technique is also useful when running programs written by other people.
+
+Here is a final challenge: enter the `commands` folder, then run the `lucky` file inside it using a relative path.

quests/execute/en/game.yml

@@ -0,0 +1,236 @@
+id: execute
+title: Running Executable Files
+image: base
+instruction: |
+  In this quest, you will learn:
+  1. What an executable file is
+  2. How to find an executable with `which`
+  3. How to run an executable file
+
+requirements:
+  - remove
+
+stages:
+  - id: start
+    name: Click Start
+    condition:
+      command: echo start
+    response:
+      content: |
+        In earlier lessons, you used commands such as `ls`, `cat`, `cp`, `mv`, and `rm`.
+        These commands are **executable files** that the operating system runs when you enter them.
+        For most commands, you can find the corresponding file in the file system.
+        Use `which` to find the file associated with a command.
+        Enter `which [command name]` to display its path.
+      hint: Use `which ls` to find the path to `ls`
+
+  - id: which-ls
+    name: Find the path to `ls` with `which`
+    requirements:
+      - start
+    condition:
+      command: which ls
+    response:
+      content: |
+        The terminal displays `/usr/bin/ls`, the location of the `ls` executable.
+        `/usr/bin` is a system folder containing many standard programs.
+
+        Next, let's find the path to `cat`.
+      hint: Use `which cat` to find the path to `cat`
+
+  - id: which-cat
+    name: Find the path to `cat` with `which`
+    requirements:
+      - which-ls
+    condition:
+      command: which cat
+    response:
+      content: |
+        You can see `/usr/bin/cat`, which is also in the `/usr/bin` folder.
+        To run an executable file, **enter its path directly**.
+        Let's try running a command using the path to its executable.
+
+        First, let's see what happens when you run `ls` normally.
+      hint: Enter `ls` to list the contents of your current folder
+
+  - id: ls
+    name: List the current folder with `ls`
+    requirements:
+      - which-cat
+    condition:
+      command: ls
+    response:
+      content: |
+        Your current folder contains the `commands` folder and two files, `dog` and `hello.txt`.
+        Now try running `ls` using its absolute path, `/usr/bin/ls`.
+      hint: Enter `/usr/bin/ls` to list the contents of your current folder
+
+  - id: bin-ls
+    name: Run `ls` using its absolute path
+    requirements:
+      - ls
+    condition:
+      command: /usr/bin/ls
+    exceptions:
+      - id: exception-ls
+        condition:
+          command: ls
+        response:
+          content: |
+            Here, we are practicing running `ls` using its absolute path.
+            Enter `/usr/bin/ls` to list the contents of your current folder.
+    response:
+      content: |
+        It lists the same files as `ls`. Both commands run the program at `/usr/bin/ls`, so the results are the same.
+
+        You can still pass arguments. Try using `/usr/bin/cat` to display the contents of `hello.txt`.
+      hint: Enter `/usr/bin/cat hello.txt`
+
+  - id: bin-cat
+    name: Run `cat` using its absolute path
+    requirements:
+      - bin-ls
+    condition:
+      command: /usr/bin/cat hello.txt
+    response:
+      content: |
+        You can see the contents of `hello.txt`, just as you would with `cat`.
+        Both commands run the program at `/usr/bin/cat`, so the results are the same.
+
+        A command usually has the form `command argument1 argument2 ...`.
+        The `command` is the name or path of the program to run, such as `ls`, `cat`, or `which`.
+        The `arguments` provide information to the program, such as `hello.txt` after `cat`.
+
+        You can enter `ls` instead of `/usr/bin/ls` because an environment variable called `PATH` tells the shell which folders to search for programs.
+        We will learn more about `PATH` in a future lesson.
+
+        Now let's try running a custom command.
+        The file named `dog` in this folder is a custom command provided for this lesson.
+        First, let's see what is written inside it.
+      hint: Use `cat dog` to display the contents of `dog`
+
+  - id: cat-dog
+    name: Display the contents of `dog` with `cat`
+    requirements:
+      - bin-cat
+    condition:
+      command: cat dog
+    response:
+      content: |
+        This is a simple program built from `echo` and `sleep` commands.
+        You do not need to understand every detail yet. It just prints a few lines of text.
+
+        To run a file, specify its path.
+        Here, the first part of the command is the path to `dog`. This example does not use any arguments.
+        Since `dog` is in your home folder, its absolute path is `/home/commander/dog`.
+        Using the format `executable arguments`, the command is:
+        ```
+        /home/commander/dog
+        ```
+      hint: Enter `/home/commander/dog` to run the `dog` file
+
+  - id: dog-abs
+    name: Run `dog` using an absolute path
+    requirements:
+      - cat-dog
+    condition:
+      or:
+        - command: /home/commander/dog
+        - command: ~/dog
+    exceptions:
+      - id: exception-dog
+        condition:
+          command: dog
+          error: 'command not found: dog'
+        response:
+          content: |
+            `dog` cannot be run by name here because it is not in the command search path. Specify the path to its executable file.
+            Here, we are practicing running `dog` using an absolute path.
+            Enter `/home/commander/dog` to run the `dog` file.
+    response:
+      content: |
+        The terminal displays a few words from this dog with an attitude.
+        When you are in the same folder as a program, a relative path is often more convenient than an absolute path.
+        To run a program in your current folder, put `./` before its filename instead of entering just its name.
+        In a path, `.` means the current folder.
+        Now try running `dog` using a relative path.
+      hint: Enter `./dog` to run the `dog` file
+
+  - id: dog-rel
+    name: Run `dog` using a relative path
+    requirements:
+      - dog-abs
+    condition:
+      pwd: /home/commander
+      command: ./dog
+    exceptions:
+      - id: exception-dog-2
+        condition:
+          command: dog
+          error: 'command not found: dog'
+        response:
+          content: |
+            `dog` cannot be run by name here because it is not in the command search path. Specify the path to its executable file.
+            Here, we are practicing running `dog` using a relative path.
+            Enter `./dog` to run the `dog` file.
+    response:
+      content: |
+        The dog produces the same output as before.
+        This is an example of a simple custom command.
+        You can put a sequence of commands in a file and run them together to handle complex or repetitive tasks.
+        This technique is also useful when running programs written by other people.
+
+        Here is a final challenge: enter the `commands` folder, then run the `lucky` file inside it using a relative path.
+      hint: |
+        Use `cd` to enter a folder
+        Use `ls` to list the files
+        Enter `./filename` to run a file
+
+  - id: execute-lucky
+    name: Run `lucky` using a relative path
+    requirements:
+      - dog-rel
+    condition:
+      pwd: /home/commander/commands
+      command: ./lucky
+    response:
+      content: |
+        The terminal displays `I am SO LUCKY!!!`, the message printed by `lucky`.
+        Congratulations! You have completed this lesson!
+        Enter `echo finish` to complete this quest.
+    exceptions:
+      - id: exception-lucky
+        condition:
+          command: lucky
+          error: 'command not found: lucky'
+        response:
+          content: |
+            `lucky` cannot be run by name here because it is not in the command search path. Specify the path to its executable file.
+
+      - id: exception-lucky-2
+        condition:
+          pwd: /home/commander
+          command: ./lucky
+          error: 'no such file or directory'
+        response:
+          content: |
+            You are outside the `commands` folder, so `./lucky` does not point to the file yet.
+            First, enter `cd commands` to move into `commands`. Then enter `./lucky` to run `lucky` using a relative path.
+      - id: help
+        condition:
+          command: echo help
+        response:
+          content: |
+            Enter the `commands` folder before running `lucky` using a relative path.
+            First, enter `cd commands` to move into `commands`. Then enter `./lucky` to run `lucky` using a relative path.
+
+  - id: END
+    name: Congratulations! All tasks completed!
+    requirements:
+      - execute-lucky
+    condition:
+      command: echo finish
+    response:
+      content: |
+        Congratulations! You have completed this lesson!
+        You now know how to run executable files.

quests/execute/en/home/commands/lucky

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+echo "I am SO LUCKY!!!"

quests/execute/en/home/dog

@@ -0,0 +1,8 @@
+#!/bin/sh
+
+echo "You ran the dog file"
+echo "Woof woof woof"
+sleep 1
+echo "You know what?"
+sleep 1
+echo "I am better than a cat"

quests/execute/en/home/hello.txt

@@ -0,0 +1 @@
+Hello! This is a file hello.txt

quests/explore/en/answer.sh

@@ -0,0 +1,8 @@
+echo start
+ls
+cd folder1
+ls
+cd ..
+cd folder2
+ls
+cd ..

quests/explore/en/game.yml

@@ -0,0 +1,161 @@
+id: explore
+image: base
+title: Exploring Files
+instruction: |
+  In this quest, you will learn:
+  1. How to list folder contents with `ls`
+  2. How to move between folders with `cd`
+
+requirements:
+  - get-started
+
+stages:
+  - id: start
+    name: Click `Start` to begin the lesson
+    condition:
+      command: ^echo start$
+    response:
+      content: |
+        The terminal has no graphical interface for browsing folder contents.
+        Instead, you can use `ls` to list what is inside a folder.
+        `ls` is short for list. Its first character is a lowercase L.
+        When you enter `ls`, the terminal lists the files and folders in your current folder.
+        Now enter `ls` to see what is in this folder.
+      hint: Enter `ls` to list the contents of the folder
+
+  - id: ls
+    name: List the files in the folder
+    requirements:
+      - start
+    condition:
+      command: ^ls$
+    exceptions:
+      - id: wrong_directory
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          type: narrative
+          content: |
+            First, return to `/home/commander/`
+            Enter `cd ~` to return to `/home/commander/`
+    response:
+      content: |
+        You should now see the contents of the folder.
+        The file tree on the right has changed too.
+        This folder contains two folders named `folder1` and `folder2`.
+
+        Next, let's learn how to enter a folder.
+        `cd` is short for change directory, which means changing your current folder.
+        Enter `cd [folder name]` to move into a folder.
+        For example, enter `cd folder1` to move into `folder1`.
+        Now enter the `folder1` folder.
+      hint: Enter `cd folder1` to move into `folder1`
+
+  - id: cd-folder1
+    name: Enter `folder1`
+    requirements:
+      - ls
+    condition:
+      pwd: /home/commander/folder1
+    exceptions:
+      - id: wrong_spelling
+        condition:
+          command: ^folderl$
+        response:
+          type: narrative
+          content: |
+            `folder1` ends with the number `1`, not the letter `l`.
+      - id: wrong_directory
+        condition:
+          pwd: /home/commander
+        response:
+          type: narrative
+          content: Enter `cd folder1` to move into `folder1`
+      - id: not_in_home
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          type: narrative
+          content: |
+            First, return to `/home/commander/`
+            Enter `cd ~` to return to `/home/commander/`
+            Then enter `cd folder1` to move into `folder1`
+    response:
+      content: |
+        You have entered the `folder1` folder.
+        Notice that the command prompt has changed from
+        `commander:~ $` to
+        `commander:~/folder1 $`.
+        This tells you that you are now in `folder1`.
+        Now list the contents of `folder1`.
+      hint: Enter `ls` to list the contents of the folder
+
+  - id: ls-folder1
+    name: List the contents of `folder1`
+    requirements:
+      - cd-folder1
+    condition:
+      pwd: /home/commander/folder1
+      command: ^ls$
+    response:
+      content: |
+        You can see two files in `folder1`, named `file1.txt` and `file2.txt`.
+        Now let's leave `folder1` and return to the original folder.
+        Use `cd ..` to move up to the parent folder.
+        Here, `..` means the parent folder.
+      hint: Enter `cd ..` to move up to the parent folder
+
+  - id: cd_up
+    name: Return to the parent folder
+    requirements:
+      - ls-folder1
+    condition:
+      pwd: /home/commander
+    response:
+      content: |
+        You have returned to the parent folder.
+        Use the commands you just learned to enter `folder2`, list its contents, and return to this folder.
+      hint: |
+        Use `cd` to move between folders
+        Use `ls` to list the contents of a folder
+
+  - id: cd-folder2
+    name: Enter `folder2`
+    requirements:
+      - cd_up
+    condition:
+      pwd: /home/commander/folder2
+    response:
+      content: |
+        You have entered the `folder2` folder.
+        Now list the contents of `folder2`.
+      hint: Use `ls` to list the contents of the folder
+
+  - id: ls-folder2
+    name: List the contents of `folder2`
+    requirements:
+      - cd-folder2
+    condition:
+      pwd: /home/commander/folder2
+      command: ^ls$
+    response:
+      content: |
+        You can see two files in `folder2`, named `file3.txt` and `file4.txt`.
+        Now leave `folder2` and return to the original folder.
+      hint: Use `cd ..` to move up to the parent folder
+
+  - id: END
+    name: Return to the original folder
+    requirements:
+      - ls-folder2
+    condition:
+      pwd: /home/commander
+    response:
+      content: |
+        You have returned to the original folder.
+        Congratulations! You now know how to use `ls` and `cd`.
+      hint: |
+        Use `cd` to move between folders
+        Use `ls` to list the contents of a folder

quests/get-started/en/answer.sh

@@ -0,0 +1,4 @@
+echo start
+echo hello
+echo next
+echo finish

quests/get-started/en/game.yml

@@ -0,0 +1,76 @@
+id: get-started
+image: base
+title: Terminal Basics
+instruction: |
+  Welcome to Linux Odyssey!
+  This quest introduces the basics of using the terminal.
+  In this quest, you will learn:
+  1. How to use this website
+  2. How to use the terminal
+  3. How to use the `echo` command
+
+stages:
+  - id: start
+    name: Click `Start` to begin
+    condition:
+      command: ^echo start$
+    response:
+      content: |
+        Hello, brave adventurer!
+        Welcome to Linux Odyssey, an adventure filled with terminal magic!
+        Think of the terminal as your magic wand. You control the computer with **text spells**, a useful skill for any aspiring programmer!
+        The area below is your stage for casting spells: the terminal. Ready to cast your first one?
+        Enter `echo hello` below, then press Enter to see what happens!
+
+  - id: echo-hello
+    name: Enter `echo hello` in the terminal
+    requirements:
+      - start
+    condition:
+      command: ^echo hello$
+    response:
+      content: |
+        Congratulations on running your first command!
+        You should see this in the terminal:
+        ```
+        commander:~ $ echo hello
+        hello
+        ```
+        The prompt `commander:~ $` means the computer is waiting for a command.
+        After you enter `echo hello`, the computer prints "hello" on the next line.
+
+        A command is like a sentence telling the computer what to do.
+        Take `echo hello`, for example:
+        - `echo` tells the computer to print something
+        - `hello` is the text to print
+        So when you enter `echo hello`, the computer prints "hello".
+
+        Now try making the terminal display the text `next`.
+        If you get stuck, click the `Hint` button for help.
+      hint: |
+        Enter `echo next` to continue to the next step.
+
+  - id: echo-next
+    name: Enter `echo next` in the terminal
+    requirements:
+      - echo-hello
+    condition:
+      command: ^echo next$
+    response:
+      content: |
+        Congratulations! You now know how to use `echo`.
+        You might wonder why we need a command like this.
+        Although `echo` is simple, printing text is a basic building block for many tasks.
+        In this adventure, we will also use `echo` to trigger events.
+        That is all for this quest. Enter `echo finish` to complete it.
+
+  - id: END
+    name: Finish the quest
+    requirements:
+      - echo-next
+    condition:
+      command: ^echo finish$
+    response:
+      content: |
+        Congratulations! You have completed this quest!
+        You have learned how to use `echo` and what it does.

quests/move/en/answer.sh

@@ -0,0 +1,11 @@
+echo start
+echo next
+mv hello.txt notes
+ls
+ls notes
+echo next
+mv world.txt wow.txt
+ls
+mv notes docs
+ls
+mv docs/hello.txt hi.txt

quests/move/en/game.yml

@@ -0,0 +1,136 @@
+id: move
+title: Moving Files
+image: base
+instruction: |
+  In this quest, you will learn:
+  1. How to move files and folders with `mv`
+
+requirements:
+  - create
+
+stages:
+  - id: start
+    name: Click `Start` to begin
+    condition:
+      command: echo start
+    response:
+      content: |
+        Today we will learn how to move files and folders.
+        Your current folder contains `hello.txt`, `world.txt`, and a folder named `notes`.
+        First, use `ls` and `cat` to explore their contents.
+        When you have finished, enter `echo next` to continue!
+      hint: |
+        Use `ls` and `ls notes` to list the files in the folders
+        Use `cat hello.txt` and `cat world.txt` to display the file contents
+        When you have finished, enter `echo next` to continue
+
+  - id: next
+    requirements:
+      - start
+    name: Explore the files, then enter `echo next` to continue
+    condition:
+      command: echo next
+    response:
+      content: |
+        Now let's learn how to move files and folders.
+        `mv` is short for move. It moves files and folders.
+        Use `mv [source] [destination]`.
+        Let's start by moving `hello.txt` into the `notes` folder!
+      hint: Use `mv hello.txt notes` to move `hello.txt` into `notes`
+
+  - id: mv-hello
+    requirements:
+      - next
+    name: Move `hello.txt` into `notes`
+    condition:
+      command: mv hello.txt notes
+      files:
+        - path: /home/commander/notes/hello.txt
+          type: file
+          exists: true
+        - path: /home/commander/hello.txt
+          type: file
+          exists: false
+    response:
+      content: |
+        Well done!
+        `hello.txt` has been moved into `notes`!
+
+        `mv` can also rename files!
+        Just use the new name as the destination.
+        Now rename `world.txt` to `wow.txt`.
+      hint: Use `mv world.txt wow.txt` to rename `world.txt` to `wow.txt`
+
+  - id: mv-world
+    requirements:
+      - mv-hello
+    name: Rename `world.txt` to `wow.txt`
+    condition:
+      command: mv world.txt wow.txt
+      files:
+        - path: /home/commander/wow.txt
+          type: file
+          exists: true
+        - path: /home/commander/world.txt
+          type: file
+          exists: false
+    response:
+      content: |
+        `world.txt` is now named `wow.txt`.
+
+        Next, let's learn how to move folders!
+        Moving a folder works the same way as moving a file.
+        `mv` automatically moves everything inside the folder too.
+        First, rename the `notes` folder to `docs`!
+      hint: Use `mv notes docs` to rename `notes` to `docs`
+
+  - id: mv-notes
+    requirements:
+      - mv-world
+    name: Rename `notes` to `docs`
+    condition:
+      command: mv notes docs
+      files:
+        - path: /home/commander/docs
+          type: directory
+          exists: true
+        - path: /home/commander/notes
+          type: directory
+          exists: false
+    response:
+      content: |
+        The `notes` folder is now named `docs`.
+        Here is a final challenge:
+        Move `docs/hello.txt` to your home folder and rename it to `hi.txt`.
+      hint: Use `mv docs/hello.txt hi.txt` to move the file to your home folder as `hi.txt`
+
+  - id: mv-docs-hello
+    requirements:
+      - mv-notes
+    name: Move `docs/hello.txt` to your home folder as `hi.txt`
+    condition:
+      command: mv docs/hello.txt hi.txt
+      files:
+        - path: /home/commander/hi.txt
+          type: file
+          exists: true
+        - path: /home/commander/docs/hello.txt
+          type: file
+          exists: false
+    response:
+      content: |
+        Well done!
+        You now know how to move files and folders!
+
+        Enter `echo finish` to complete this quest.
+
+  - id: END
+    requirements:
+      - mv-docs-hello
+    name: Complete the quest
+    condition:
+      command: echo finish
+    response:
+      content: |
+        You now know how to move files and folders!
+        Congratulations on completing this quest!

quests/move/en/home/hello.txt

@@ -0,0 +1 @@
+Hello

quests/move/en/home/notes/note.txt

@@ -0,0 +1 @@
+Note

quests/move/en/home/world.txt

@@ -0,0 +1 @@
+World

quests/path/en/answer.sh

@@ -0,0 +1,8 @@
+echo start
+ls
+cd folder1
+cd ../folder2
+ls ../folder1
+pwd
+ls ~
+cd ~

quests/path/en/game.yml

@@ -0,0 +1,146 @@
+id: path
+title: File Paths
+image: base
+instruction: |
+  In this quest, you will learn:
+  1. Absolute and relative paths
+  2. How to show your current path with `pwd`
+
+requirements:
+  - explore
+
+stages:
+  - id: start
+    name: Click `Start` to begin the lesson
+    condition:
+      command: echo start
+    response:
+      content: |
+        In Linux, a path describes the location of a file or folder.
+        Paths can be relative or absolute.
+        A relative path starts from your current folder. An absolute path starts from the root folder.
+        First, use `ls` to list the files in this folder.
+
+  - id: ls
+    name: List the files in the folder
+    requirements:
+      - start
+    condition:
+      pwd: /home/commander
+      command: ls
+    response:
+      content: |
+        Now use `cd` to enter the `folder1` folder.
+
+  - id: cd-folder1
+    name: Enter `folder1`
+    requirements:
+      - ls
+    condition:
+      pwd: /home/commander/folder1
+    response:
+      content: |
+        You have entered `folder1`.
+        In `cd folder1`, the `folder1` part is a relative path.
+        Likewise, `..` in `cd ..` is a relative path.
+        A relative path can span more than one level of folders.
+        For example, to enter `folder2` from here, you could use `cd ..` to go up one level, then `cd folder2` to enter it.
+        You can also join `..` and `folder2` with `/` and enter `cd ../folder2` to get there in one command.
+        Try entering `folder2` this way.
+      hint: Enter `cd ../folder2` to move into `folder2`.
+
+  - id: cd-folder2
+    name: Enter `folder2`
+    requirements:
+      - cd-folder1
+    condition:
+      pwd: /home/commander/folder2
+    exceptions:
+      - id: not_in_folder2
+        condition:
+          pwd: /home/commander
+        response:
+          content: Enter `cd folder2` to move into `folder2`
+    response:
+      content: |
+        You have entered `folder2` using a relative path.
+        You can also add a relative path after `ls` to list the contents of another folder.
+        For example, use `ls ../folder1` to see which files are in `folder1`.
+        Try listing the files in `folder1` this way.
+      hint: Enter `ls ../folder1` to list the files in `folder1`.
+
+  - id: ls-folder1
+    name: List the files in `folder1`
+    requirements:
+      - cd-folder2
+    condition:
+      output: file1.txt
+    exceptions:
+      - id: not_in_folder2
+        condition:
+          not:
+            pwd: /home/commander/folder2
+        response:
+          content: Return to `folder2` with `cd ~/folder2`, then use `ls ../folder1` to list the contents of `folder1` without leaving `folder2`.
+    response:
+      content: |
+        Great! You now know how to use relative paths.
+        Next, let's look at absolute paths.
+        An absolute path starts from the root folder, which is at the top of the file tree.
+        Use `pwd` to display the absolute path to your current folder.
+        `pwd` stands for `print working directory`: it displays the path to the folder you are in.
+        Now use `pwd` to display your current absolute path.
+      hint: Enter `pwd` to display your current absolute path
+
+  - id: pwd
+    name: Display your current absolute path
+    requirements:
+      - ls-folder1
+    condition:
+      pwd: /home/commander/folder2
+      command: pwd
+    exceptions:
+      - id: not_in_folder2
+        condition:
+          not:
+            pwd: /home/commander/folder2
+        response:
+          content: Return to `folder2`, then use `pwd` to display your current absolute path
+    response:
+      content: |
+        Your current absolute path is `/home/commander/folder2`.
+        The command prompt also shows your current location.
+        In `commander:~/folder2 $`, `~/folder2` is a shortened form of the path to your current folder.
+        `~` stands for `/home/commander`, your home folder. Each game starts here.
+        You can use absolute paths with `ls` and `cd` too.
+        For example, use `ls ~` to list your home folder or `cd ~` to return to it.
+        Now use `ls ~` to list the contents of your home folder.
+      hint: Enter `ls ~` to list the contents of your home folder
+
+  - id: ls_home
+    name: List the contents of your home folder
+    requirements:
+      - pwd
+    condition:
+      command: ls ~
+    response:
+      content: |
+        Now use `cd ~` to return to your home folder.
+      hint: Enter `cd ~` to return to your home folder
+
+  - id: END
+    name: Return to your home folder
+    requirements:
+      - ls_home
+    condition:
+      command: cd ~
+    exceptions:
+      - id: already_home
+        condition:
+          pwd: /home/commander
+        response:
+          content: Use `cd ~` to return to your home folder
+    response:
+      content: |
+        You have returned to your home folder.
+        Congratulations! You now know how to use absolute and relative paths and display your current absolute path.

quests/read/en/answer.sh

@@ -0,0 +1,5 @@
+echo start
+ls
+cat file1.txt
+ls folder
+cat folder/file.txt

quests/read/en/game.yml

@@ -0,0 +1,93 @@
+id: read
+title: Reading File Contents
+image: base
+instruction: |
+  In this quest, you will learn:
+  1. How to display file contents with `cat`
+
+requirements:
+  - path
+
+stages:
+  - id: start
+    name: Click `Start` to begin the lesson
+    condition:
+      command: echo start
+    response:
+      content: |
+        The terminal has no graphical interface for viewing file contents.
+        Instead, you can use `cat` to display them.
+        `cat` is short for concatenate, which means joining things together.
+        Enter `cat [filename]` to print a file's contents in the terminal.
+        First, see which files are in this folder.
+      hint: Enter `ls` to list the files in this folder.
+
+  - id: ls_home
+    name: List the files in the folder
+    requirements:
+      - start
+    condition:
+      pwd: /home/commander
+      command: ls
+    response:
+      content: |
+        This folder contains one file and one folder.
+        Now use `cat` to display the contents of `file1.txt`.
+      hint: Enter `cat file1.txt` to display the file contents.
+
+  - id: cat-file1
+    name: Display the contents of `file1.txt`
+    requirements:
+      - ls_home
+    condition:
+      pwd: /home/commander
+      command: cat file1.txt
+    response:
+      content: |
+        You should now see the file's contents.
+        You can also give `cat` a path to a file in another folder.
+        First, use `ls folder` to list the files inside `folder`.
+      hint: Enter `ls folder` to list the files inside the folder
+
+  - id: ls-folder
+    name: List the contents of `folder`
+    requirements:
+      - cat-file1
+    condition:
+      pwd: /home/commander
+      command: ls folder
+    exceptions:
+      - id: not_in_home
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          content: |
+            Stay in the `/home/commander` folder.
+            Enter `cd ~` to return to `/home/commander`.
+    response:
+      content: |
+        You now know what is inside `folder`.
+        Use `cat` to display the contents of `file.txt` inside `folder`.
+      hint: Enter `cat folder/file.txt` to display the contents of `file.txt`.
+
+  - id: END
+    name: Display the contents of `file.txt`
+    requirements:
+      - ls-folder
+    condition:
+      pwd: /home/commander
+      command: cat folder/file.txt
+    exceptions:
+      - id: not_in_home
+        condition:
+          not:
+            pwd: /home/commander
+        response:
+          content: |
+            Stay in the `/home/commander` folder.
+            Enter `cd ~` to return to `/home/commander`.
+    response:
+      content: |
+        You have displayed the contents of `file.txt`.
+        You now know how to display file contents with `cat`.

quests/read/en/home/file1.txt

@@ -0,0 +1 @@
+This is file1.txt

quests/read/en/home/folder/file.txt

@@ -0,0 +1 @@
+This is file.txt

quests/remove/en/answer.sh

@@ -0,0 +1,14 @@
+echo start
+ls
+rm hello.txt
+ls
+rm world.txt wow.txt
+ls
+rmdir empty
+ls
+rmdir notes
+rm notes/note.txt
+rmdir notes
+ls trash
+rm -r trash
+ls

quests/remove/en/game.yml

@@ -0,0 +1,202 @@
+id: remove
+title: Deleting Files and Folders
+image: base
+instruction: |
+  In this quest, you will learn:
+  1. How to delete files with `rm`
+  2. How to delete empty folders with `rmdir`
+  3. How to delete folders and their contents with `rm -r`
+
+requirements:
+  - copy
+  - move
+
+stages:
+  - id: start
+    name: Click `Start` to begin
+    condition:
+      command: echo start
+    response:
+      content: |
+        Today we will learn how to delete files and folders.
+        Your current folder contains `hello.txt`, `world.txt`, and a folder named `notes`.
+        First, use `ls` to list them.
+        When you have finished, enter `echo next` to continue!
+      hint: |
+        Use `ls` to list the files in the folder
+        When you have finished, enter `echo next` to continue
+
+  - id: next
+    requirements:
+      - start
+    name: Explore the files, then enter `echo next` to continue
+    condition:
+      command: echo next
+    response:
+      content: |
+        Now let's learn how to delete files.
+        `rm` is short for remove. It deletes files.
+        Use `rm [filename]`.
+        Let's start by deleting `hello.txt`!
+      hint: Use `rm hello.txt` to delete `hello.txt`
+
+  - id: rm-hello
+    requirements:
+      - next
+    name: Delete `hello.txt`
+    condition:
+      command: rm hello.txt
+      files:
+        - path: /home/commander/hello.txt
+          type: file
+          exists: false
+    response:
+      content: |
+        `hello.txt` is no longer in the folder!
+
+        `rm` can delete several files at once. Separate their names with spaces.
+        Use `rm [file1] [file2] ...`.
+        Now use `rm` to delete `world.txt` and `wow.txt`.
+      hint: |
+        Use `rm world.txt wow.txt` to delete `world.txt` and `wow.txt`
+        Separate the filenames with a space
+        The order of the names does not matter
+
+  - id: rm-world-wow
+    requirements:
+      - rm-hello
+    name: Delete `world.txt` and `wow.txt`
+    condition:
+      files:
+        - path: /home/commander/world.txt
+          type: file
+          exists: false
+        - path: /home/commander/wow.txt
+          type: file
+          exists: false
+    response:
+      content: |
+        `world.txt` and `wow.txt` are now gone.
+
+        Next, let's learn how to delete folders.
+        `rmdir` deletes empty folders.
+        Use `rmdir [folder name]`.
+        Let's start by deleting the `empty` folder!
+      hint: Use `rmdir empty` to delete the `empty` folder
+
+  - id: rm-empty
+    requirements:
+      - rm-world-wow
+    name: Delete the `empty` folder
+    condition:
+      command: rmdir empty
+      files:
+        - path: /home/commander/empty
+          type: directory
+          exists: false
+    response:
+      content: |
+        The `empty` folder is now gone.
+        Now try using `rmdir` to delete the `notes` folder.
+      hint: Use `rmdir notes` to delete the `notes` folder
+
+  - id: rm-notes-failed
+    requirements:
+      - rm-empty
+    name: Try deleting the `notes` folder
+    condition:
+      command: rmdir notes
+      error: "rmdir: failed to remove 'notes': Directory not empty"
+    response:
+      content: |
+        The command failed!
+        The `notes` folder is still there.
+        This is because `rmdir` only deletes empty folders.
+        Let's delete the files inside `notes` and try again.
+        Now use `rm` to delete the files inside `notes`.
+      hint: |
+        Use `rm notes/[filename]` to delete a file inside `notes`
+        You may need to use `ls notes` to see which files are inside
+        Or use Tab to complete the filename
+
+  - id: rm-notes-content
+    requirements:
+      - rm-notes-failed
+    name: Delete the files inside `notes`
+    condition:
+      command: rm notes/note.txt
+      files:
+        - path: /home/commander/notes/note.txt
+          type: file
+          exists: false
+    exceptions:
+      - id: hint
+        condition:
+          command: echo hint
+        response:
+          content: |
+            Use `rm notes/note.txt` to delete `note.txt` inside `notes`.
+          hint: Use `rm notes/note.txt` to delete `note.txt` inside `notes`
+    response:
+      content: |
+        Great! Now use `rmdir` again to delete the `notes` folder.
+      hint: Use `rmdir notes` to delete the `notes` folder
+
+  - id: rm-notes
+    requirements:
+      - rm-notes-content
+    name: Delete the `notes` folder
+    condition:
+      command: rmdir notes
+      files:
+        - path: /home/commander/notes
+          type: directory
+          exists: false
+    response:
+      content: |
+        Great! The `notes` folder has been deleted.
+        Next, let's delete the `trash` folder.
+        First, use `ls` to see what is inside `trash`.
+      hint: Use `ls trash` to list the files inside `trash`
+
+  - id: ls-trash
+    requirements:
+      - rm-notes
+    name: List the contents of `trash`
+    condition:
+      command: ls trash
+    response:
+      content: |
+        Wow! `trash` contains lots of files, and even more folders!
+        What if a folder has many files and subfolders and we want to delete them all at once?
+        Just as with `cp`, add the `-r` option to delete the folder and everything inside it.
+        `-r` means recursive: the command also deletes the contents of any nested folders.
+        Let's try it!
+      hint: Use `rm -r trash` to delete the `trash` folder
+
+  - id: rm-trash
+    requirements:
+      - ls-trash
+    name: Delete `trash` and its contents
+    condition:
+      command: rm -r trash
+      files:
+        - path: /home/commander/trash
+          type: directory
+          exists: false
+    response:
+      content: |
+        The `trash` folder and everything inside it are now gone.
+        Congratulations! You now know how to delete files and folders!
+        Enter `echo finish` to complete this quest.
+
+  - id: END
+    requirements:
+      - rm-trash
+    name: Complete the quest
+    condition:
+      command: echo finish
+    response:
+      content: |
+        You now know how to delete files and folders!
+        Congratulations on completing this quest!

quests/remove/en/home/hello.txt

@@ -0,0 +1 @@
+Hello

quests/remove/en/home/notes/note.txt

@@ -0,0 +1 @@
+Note

quests/remove/en/home/world.txt

@@ -0,0 +1 @@
+World

quests/remove/en/home/wow.txt

@@ -0,0 +1 @@
+Wow

quests/tab/en/game.yml

@@ -0,0 +1,174 @@
+id: tab
+title: Tab Completion
+image: base
+instruction: |
+  In this quest, you will learn:
+
+  1. How to complete paths with Tab
+  2. How to handle multiple matching names
+
+  Click the button in the middle to start this quest.
+
+requirements:
+  - read
+
+stages:
+  - id: start
+    name: Click Start to begin the quest
+    condition:
+      command: echo start
+    response:
+      content: |
+        In the terminal, you work by entering text.
+        Typing takes time, and a single typo can make a command fail.
+        Autocompletion helps you fill in file paths, command names, and supported options, saving time and avoiding typos.
+
+        Before we start practicing, let's see which files are in your home folder.
+      hint: Use `ls` to list the files
+
+  - id: ls
+    name: List the files with `ls`
+    requirements:
+      - start
+    condition:
+      command: ls
+    response:
+      content: |
+        This folder is full of very long and misspelled filenames. Typing them character by character would be painful.
+        Luckily, autocompletion makes even long filenames easy to enter.
+
+        To use autocompletion, **type part of a filename, then press Tab**.
+        (Tab is the key to the left of Q.)
+        For example, type `Su` and press Tab to complete `SuperSecretPlansForWorldDomination.txt`. The terminal fills in the rest for you.
+
+        Let's display the contents of `SuperSecretPlansForWorldDomination.txt`.
+      hint: |
+        Use `cat SuperSecretPlansForWorldDomination.txt` to display the file contents
+        Type `cat Su`, then press Tab to complete the filename. Press Enter to run the command
+
+  - id: cat_super_secret
+    name: Display SuperSecretPlansForWorldDomination.txt with `cat`
+    requirements:
+      - ls
+    condition:
+      pwd: /home/commander
+      command: cat SuperSecretPlansForWorldDomination.txt
+    response:
+      content: |
+        The terminal completed `SuperSecretPlansForWorldDomination.txt` for you, saving you from typing a long name and making mistakes.
+        You can start with `S`, `Su`, `Sup`, `Super`, or even no characters at all.
+        However, the fewer characters you enter, the more likely they are to match several files.
+        We will practice handling multiple matches shortly.
+
+        Autocompletion also helps with awkward spellings. Take `ThsisAFlieNmaeWthAloOfTpyosThatisRleayHdToRaed.txt`: anyone could make a mistake typing that!
+        Use `cat` again to display the contents of `ThsisAFlieNmaeWthAloOfTpyosThatisRleayHdToRaed.txt`.
+      hint: |
+        Enter `cat ThsisAFlieNmaeWthAloOfTpyosThatisRleayHdToRaed.txt` to display the file contents
+        Type `cat Thsi`, then press Tab to complete the filename
+        Try pressing Tab after entering fewer characters and see what happens
+
+  - id: cat_typo
+    name: Display ThsisAFlieNmaeWthAloOfTpyosThatisRleayHdToRaed.txt with `cat`
+    requirements:
+      - cat_super_secret
+    condition:
+      pwd: /home/commander
+      command: cat ThsisAFlieNmaeWthAloOfTpyosThatisRleayHdToRaed.txt
+    response:
+      content: |
+        You have opened the file with the misspelled name.
+        With autocompletion, typos, mixed capitalization, and random-looking names are much easier to handle.
+        Let's practice again. This time, list the files inside `ThingsIWillOrganizeLaterWhenIHaveTime`.
+        As before, type the first few characters, then press Tab.
+      hint: |
+        Enter `ls ThingsIWillOrganizeLaterWhenIHaveTime` to list the files inside the folder
+        Type `ls Thing`, then press Tab to complete the folder name
+
+  - id: ls_things
+    name: List ThingsIWillOrganizeLaterWhenIHaveTime with `ls`
+    requirements:
+      - cat_typo
+    condition:
+      pwd: /home/commander
+      command: ls ThingsIWillOrganizeLaterWhenIHaveTime
+    response:
+      content: |
+        This folder contains three files: a guide to making sandwiches and two lists of things downloaded in the middle of the night.
+        The sandwich guide, `HowToProperlyMakeASandwich.txt`, is inside another folder, so one press of Tab will not complete the whole path.
+        This time, let's practice **completing a path in steps**.
+
+        Type the start of the folder name and press Tab. Then type the start of the filename and press Tab again to complete `folder/filename`.
+        When you complete a folder name, the terminal adds `/` at the end for you.
+        Let's open `HowToProperlyMakeASandwich.txt`.
+      hint: |
+        Enter `cat ThingsIWillOrganizeLaterWhenIHaveTime/HowToProperlyMakeASandwich.txt` to display the file contents
+        Type `cat Thin`, then press Tab to complete it to `cat ThingsIWillOrganizeLaterWhenIHaveTime/`
+        Next, type `How` after the folder path and press Tab to complete the full path
+
+  - id: cat_sandwich
+    name: Display ThingsIWillOrganizeLaterWhenIHaveTime/HowToProperlyMakeASandwich.txt with `cat`
+    requirements:
+      - ls_things
+    condition:
+      command: cat ThingsIWillOrganizeLaterWhenIHaveTime/HowToProperlyMakeASandwich.txt
+    response:
+      content: |
+        You have read this very strict guide to making a sandwich.
+        Two files remain: `RandomStuffThatIDownloadedAt3AM.txt` and `RandomStuffThatIDownloadedAt4AM.txt`.
+        Their names are almost identical. They differ only at `3AM` and `4AM` before the `.txt` extension.
+        If you only type the first few characters, the terminal cannot tell which file you want.
+        This is a case of **multiple matches**.
+
+        You can handle multiple matches in steps, just as you did with the folder path.
+        Type `Ran` and press Tab. The terminal completes the shared part of both names: `RandomStuffThatIDownloadedAt`.
+        Then type `3` or `4`, depending on which file you want, and press Tab again to complete the rest.
+
+        _Completing a full path also takes steps: after completing the folder name, you still need to choose a file inside it._
+      hint: |
+        Display the contents of `ThingsIWillOrganizeLaterWhenIHaveTime/RandomStuffThatIDownloadedAt3AM.txt`
+        Type `cat Thin`, then press Tab to complete it to `cat ThingsIWillOrganizeLaterWhenIHaveTime/`
+        Next, type `Ran` and press Tab to complete it to `cat ThingsIWillOrganizeLaterWhenIHaveTime/RandomStuffThatIDownloadedAt`
+        Then type `3` and press Tab to complete the full path.
+
+  - id: cat_3am
+    name: Display ThingsIWillOrganizeLaterWhenIHaveTime/RandomStuffThatIDownloadedAt3AM.txt with `cat`
+    requirements:
+      - cat_sandwich
+    condition:
+      pwd: /home/commander
+      command: cat ThingsIWillOrganizeLaterWhenIHaveTime/RandomStuffThatIDownloadedAt3AM.txt
+    response:
+      content: |
+        You have read a list of things downloaded at 3 AM. Hmm... that is enough internet for today.
+        Here is a final challenge: enter `ThingsIWillOrganizeLaterWhenIHaveTime`, then display the contents of `RandomStuffThatIDownloadedAt4AM.txt`.
+        Use the autocompletion skills you learned today to complete the task.
+      hint: |
+        First, use `cd` to enter ThingsIWillOrganizeLaterWhenIHaveTime
+        Then use `cat` to display RandomStuffThatIDownloadedAt4AM.txt
+        Remember to use Tab completion to save time and avoid mistakes
+
+  - id: cd_things
+    name: Enter ThingsIWillOrganizeLaterWhenIHaveTime with `cd`
+    requirements:
+      - cat_3am
+    condition:
+      pwd: /home/commander/ThingsIWillOrganizeLaterWhenIHaveTime
+    response:
+      content: |
+        Great! You have entered ThingsIWillOrganizeLaterWhenIHaveTime.
+        Now use `cat` to display the contents of `RandomStuffThatIDownloadedAt4AM.txt`.
+        Remember to use Tab completion!
+
+  - id: END
+    name: Display RandomStuffThatIDownloadedAt4AM.txt with `cat`
+    requirements:
+      - cd_things
+    condition:
+      pwd: /home/commander/ThingsIWillOrganizeLaterWhenIHaveTime
+      command: cat RandomStuffThatIDownloadedAt4AM.txt
+    response:
+      content: |
+        Congratulations! You have completed all the tasks and practiced using Tab completion.
+        This skill will make working in the terminal much easier.
+        Whether you face long filenames, complex paths, or tricky spellings, Tab completion is there to help!
+      hint: All tasks completed! You can keep exploring or finish this quest.

quests/tab/en/home/SuperSecretPlansForWorldDomination.txt

@@ -0,0 +1,10 @@
+1. Collect all the socks in the world so nobody can find a matching pair.
+2. Train an army of penguins to conquer the world with cuteness.
+3. Invent a device that turns everyone's speech into chicken noises.
+4. Replace all coffee with decaf and watch the world descend into chaos.
+5. Erase every national border with a giant eraser and declare Earth one huge playground.
+6. Make all politicians wear clown costumes when giving speeches.
+7. Replace every math textbook with a cookbook and see what happens.
+8. Invent a perfume that makes people tell the truth, then spray it at the UN General Assembly.
+9. Use a giant magnet to collect all the metal on Earth and build a Disneyland in space.
+10. If all else fails, flood the world's social media with cute cat videos until everyone surrenders.

quests/tab/en/home/ThingsIWillOrganizeLaterWhenIHaveTime/HowToProperlyMakeASandwich.txt

@@ -0,0 +1,9 @@
+How to Make a Sandwich "Properly":
+
+1. Slap your bread awake. It has been loafing around all day!
+2. Choose your ingredients carefully. Each one must have its own personality. For example, pick a slice of ham that loves telling jokes.
+3. Measure the thickness of each ingredient with a ruler. The margin of error must be no more than 1 mm.
+4. Wear white gloves and laboratory goggles while assembling the sandwich to ensure the highest standards of hygiene.
+5. Once finished, inspect every inch of the sandwich with a magnifying glass to make sure it is flawless.
+
+Remember: making a sandwich is an exact science. No mistakes or creativity allowed!

quests/tab/en/home/ThingsIWillOrganizeLaterWhenIHaveTime/RandomStuffThatIDownloadedAt3AM.txt

@@ -0,0 +1,5 @@
+Things I started downloading at 3 AM but never had time to organize.
+
+1. Blueprints for a magic wand that turns any food into pizza
+2. A secret guide to learning ten alien languages in five minutes
+3. A tutorial video on making fashionable hats from old socks (link no longer works)

quests/tab/en/home/ThingsIWillOrganizeLaterWhenIHaveTime/RandomStuffThatIDownloadedAt4AM.txt

@@ -0,0 +1,5 @@
+Things I started downloading at 4 AM but never had time to organize.
+
+1. A paper explaining in detail why cats are the true rulers of Earth
+2. A wikiHow article on repairing the International Space Station with chewing gum and paper clips
+3. A complete course syllabus for training jellyfish as underwater detectives

quests/tab/en/home/ThsisAFlieNmaeWthAloOfTpyosThatisRleayHdToRaed.txt

@@ -0,0 +1,3 @@
+Congrats! You fond a flie namd by somone who cleerly had a strok. If you can raed this, you mght be a geenius or jsut realy gud at Wheel of Fortnue.
+
+Remeber: freinds don't let freinds name files aftr drinkng too much. But hey, at lest you used tab compltion to get here!

quests/tab/en/tab.md

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+# Using Tab Completion
+
+In this quest, you will learn:
+
+1. How to complete paths with Tab
+2. How to handle multiple matching names
+
+Click the button in the middle to start this quest.
+
+---
+
+In the terminal, you work by entering text.
+Typing takes time, and a single typo can make a command fail.
+Autocompletion helps you fill in file paths, command names, and supported options, saving time and avoiding typos.
+
+Before we start practicing, let's see which files are in your home folder.
+
+> Use `ls` to list the files
+
+---
+
+This folder is full of very long and misspelled filenames. Typing them character by character would be painful.
+Luckily, autocompletion makes even long filenames easy to enter.
+
+To use autocompletion, **type part of a filename, then press Tab**.
+(Tab is the key to the left of Q.)
+For example, type `Su` and press Tab to complete `SuperSecretPlansForWorldDomination.txt`. The terminal fills in the rest for you.
+
+Let's display the contents of `SuperSecretPlansForWorldDomination.txt`.
+
+> Use `cat SuperSecretPlansForWorldDomination.txt` to display the file contents
+> Type `cat Su`, then press Tab to complete the filename. Press Enter to run the command
+
+---
+
+The terminal completed `SuperSecretPlansForWorldDomination.txt` for you, saving you from typing a long name and making mistakes.
+You can start with `S`, `Su`, `Sup`, `Super`, or even no characters at all.
+However, the fewer characters you enter, the more likely they are to match several files.
+We will practice handling multiple matches shortly.
+
+Autocompletion also helps with awkward spellings. Take `ThsisAFlieNmaeWthAloOfTpyosThatisRleayHdToRaed.txt`: anyone could make a mistake typing that!
+Use `cat` again to display the contents of `ThsisAFlieNmaeWthAloOfTpyosThatisRleayHdToRaed.txt`.
+
+> Enter `cat ThsisAFlieNmaeWthAloOfTpyosThatisRleayHdToRaed.txt` to display the file contents
+> Type `cat Thsi`, then press Tab to complete the filename
+> Try pressing Tab after entering fewer characters and see what happens
+
+---
+
+You have opened the file with the misspelled name.
+With autocompletion, typos, mixed capitalization, and random-looking names are much easier to handle.
+Let's practice again. This time, list the files inside `ThingsIWillOrganizeLaterWhenIHaveTime`.
+As before, type the first few characters, then press Tab.
+
+> Enter `ls ThingsIWillOrganizeLaterWhenIHaveTime` to list the files inside the folder
+> Type `ls Thing`, then press Tab to complete the folder name
+
+---
+
+This folder contains three files: a guide to making sandwiches and two lists of things downloaded in the middle of the night.
+The sandwich guide, `HowToProperlyMakeASandwich.txt`, is inside another folder, so one press of Tab will not complete the whole path.
+This time, let's practice **completing a path in steps**.
+
+Type the start of the folder name and press Tab. Then type the start of the filename and press Tab again to complete `folder/filename`.
+When you complete a folder name, the terminal adds `/` at the end for you.
+Let's open `HowToProperlyMakeASandwich.txt`.
+
+> Enter `cat ThingsIWillOrganizeLaterWhenIHaveTime/HowToProperlyMakeASandwich.txt` to display the file contents
+> Type `cat Thin`, then press Tab to complete it to `cat ThingsIWillOrganizeLaterWhenIHaveTime/`
+> Next, type `How` after the folder path and press Tab to complete the full path
+
+---
+
+You have read this very strict guide to making a sandwich.
+Two files remain: `RandomStuffThatIDownloadedAt3AM.txt` and `RandomStuffThatIDownloadedAt4AM.txt`.
+Their names are almost identical. They differ only at `3AM` and `4AM` before the `.txt` extension.
+If you only type the first few characters, the terminal cannot tell which file you want.
+This is a case of **multiple matches**.
+
+You can handle multiple matches in steps, just as you did with the folder path.
+Type `Ran` and press Tab. The terminal completes the shared part of both names: `RandomStuffThatIDownloadedAt`.
+Then type `3` or `4`, depending on which file you want, and press Tab again to complete the rest.
+
+_Completing a full path also takes steps: after completing the folder name, you still need to choose a file inside it._
+
+> Enter `cat ThingsIWillOrganizeLaterWhenIHaveTime/RandomStuffThatIDownloadedAt3AM.txt` to display the file contents
+> Type `cat Thin`, then press Tab to complete it to `cat ThingsIWillOrganizeLaterWhenIHaveTime/`
+> Next, type `Ran` and press Tab to complete it to `cat ThingsIWillOrganizeLaterWhenIHaveTime/RandomStuffThatIDownloadedAt`
+> Then type `3` and press Tab to complete the full path.
+
+---
+
+You have read a list of things downloaded at 3 AM. Hmm... that is enough internet for today.
+Here is a final challenge: enter `ThingsIWillOrganizeLaterWhenIHaveTime`, then display the contents of `RandomStuffThatIDownloadedAt4AM.txt`.
+Use the autocompletion skills you learned today to complete the task.