Meeting 1 Notes: Terminal Basics (GameShell)

While there's some really cool and wacky software that we will explore in this club, it's important to have basic terminal skills.
Hence, our first (technically second) meeting is on terminal basics.
And what better way to learn than by playing a game!

First, we'll learn a couple basic commands. Then, we'll use those skills (and some more we'll pick up on the way) to play GameShell, a terminal-based game specifically designed for learning the terminal!

Terminal Usage

A terminal is a text based interface to talk directly to your computer. Usually, you click buttons and use a graphical user interface (GUI), but here, you type commands. Commands are simply programs that can be run. For example, the firefox command will run the firefox program and launch the Firefox browser. When you enter something into the terminal's prompt (where you type stuff), it sends the text to a program called the shell. The shell will look for the command and run what it finds, say what you typed was wrong, or some error. Most of the commands used on a day-to-day basis will complete tasks such as creating files, moving data, or running programs on your computer.

pwd: Seeing Your Current Directory

The terminal always has a location inside the file system of the computer. To know what directory (a folder) you are currently located in (aka your current working directory), use the pwd (print working directory) command.

cd: Moving Around

To change directories, use the cd command followed by the directory you would like to go to (as an argument).

If I am currently in the directory /home/user/Downloads, and I want to go to /home/user/Downloads/folder, I would run cd /home/user/Downloads/folder, or just cd folder.^[1]

Important note:
In the terminal, there are a couple shorthands to make your life a bit easier:

• . means "this directory" (in this context). Hence, if I ran cd ., nothing would change because I would be in the same directory as before
• .. means "the directory immediately before the current working directory. Meaning if I am in /home/user and I want to go to /home, I would run cd ..

ls: Listing Contents of Directories

To list all the contents of a directory, use the ls command.

• If you provide a path to a directory (as an argument), you can list the contents of that directory. For example, ls /home/user would list all the contents of that folder instead of the one I'm currently located in.
• If you just run ls, you would list the contents of the current working directory, same as ls ..
• If you add an additional option starting with - (such as ls -l), you would list out the files in your current working directory in list format. You can run ls --help to see more additional options.

If I am in /home and I want to list the contents in /home/user/Downloads, I can run ls /home/user/Downloads or ls user/Downloads.

Important note:
Commands usually need some sort of input or maybe a certain option describing how it is to be run.
They usually follow the simple pattern:

command + options + arguments

• command is the name of the command, like ls.
• options are settings (flags) describing how to run the command. For example, ls's flag -a will list files, including hidden ones (files that start with a .).

cat: Printing a File's Contents

To print a file's contents to the terminal, you can run cat followed by a filename/path to a file, as an argument.

If I am in /home and I want to "cat" (print out) /home/info.txt, I would run cat /home/info.txt, or cat info.txt.

man: Reading the Manual

For most commands, there are a lot of flags and interesting quirks.
It's hard to know all these commands, so check the man page for the command, as most have one.

By running man command, where command is the name of the command, a manual page with info on the command will now be shown in the terminal.

file: Checking a File's Type

Because file extensions are not always accurate (or present!), it is useful to be able to check what type of file you are handling.

If I have a file mystery in my current working directory, I would run file mystery to get more information about the file.

GameShell

As mentioned earlier, GameShell is the terminal game we'll be playing to teach members terminal basics. Here is some history of GameShell from its GitHub page:

Teaching first-year university students or high schoolers to use a Unix shell is not always the easiest or most entertaining of tasks. GameShell was devised as a tool to help students at the Université Savoie Mont Blanc to engage with a real shell, in a way that encourages learning while also having fun.

The original idea, due to Rodolphe Lepigre, was to run a standard bash session with an appropriate configuration file that defined "missions" which would be "checked" in order to progress through the game.

Getting Started

If this does not work right away, read the bottom of the GameShell GitHub page for more info.

The commands to start are these two here:
(NOTE: In most cases on the web, lines starting with $ means enter this command as your user, so you don't include the $ in your command)

$ wget https://github.com/phyver/GameShell/releases/download/latest/gameshell.sh
$ bash gameshell.sh

You can also clone the repository and alternatively run the game with the following commands:

$ git clone https://github.com/phyver/GameShell
$ ./start.sh

First Steps

Follow the steps shown on screen.
It's useful to read the directions/explanations shown on the scroll.

As shown on the screen, run gsh goal to see the first goal. This is to go to the top of the main tower in the castle.
Also, note that there is a list of commands. As you go on, you will see commands you may not know. Using this explanation and the man pages for these commands will be very useful.

First, running ls shows us there is a Castle directory.

To go into the Castle, we can run cd Castle, and then running ls shows us there is a Main_tower directory we can go into.

Continuing this process brings us to the Top_of_the_tower.

Then, we run gsh check and see that we have completed this mission. Note that running gsh check while in any mission will check to see if you have completed the mission successfully.

Now, we can move on to the rest of these missions and enjoy playing the rest of the game!