1. Automating cool things

Helpful Notes

The shell is what we use to send commands directly to the kernel.
'Shell' and 'Terminal' are generally the same thing.
The term directory means the same thing as folder.
The ~ symbol represents the home directory in both Linux and Unix (MacOS is UNIX).
Everything in Linux is a file.
Every command begins with a program name.
You can learn more about the program using the man program.

You can open your terminal in MacOS by searching for it in Spotlight.

For windows users, do Win+X, I to open the terminal.

It will probably open in the default Powershell/CMD profile, click the dropdown and switch to Ubuntu.

Terminal

man cd

Press q to quit. You can put almost any program after the man command to learn more about it. You can even do man man.

We recommend typing in the commands by hand rather than copy-pasting, because:

You'll learn quicker
You'll be quicker
You'll retain the information better
You'll become more comfortable with the terminal

See current location

To see where we currently are, we use pwd.

Terminal

pwd

Your output can be different, but will definitely have slashes like this:

/home/yourusername

pwd means 'print current directory'. This is our current location.

See files in current location

To see what files and directories are around us, we use ls.

Terminal

ls

ls means 'list'.

ls -a will show us all of our files and directories, including hidden ones.

Terminal

ls -a

Go to the home directory

To move between directories, we use the cd command.

Terminal

cd ~

cd means 'change directory'. You can use pwd again to see where you are.

Make a directory called `workspace`

To create directories, we use the mkdir command.

Terminal

mkdir workspace

mkdir means (make directory) command

Go into the `workspace` directory

Terminal

cd workspace

Terminal

mkdir hack-the-tunnels-git-workshop

Go into the `hack-the-tunnels-git-workshop` directory

Terminal

cd hack-the-tunnels-git-workshop

Try the `echo` command

Terminal

echo "Hack the Tunnels"

You will then see the output:

Hack the Tunnels

This command is used to print things, just like print() in Python, and console.log() in JavaScript. Replace the text between the double quotes with anything you like and try again :)

man echo if you want to learn more. You can quit man pages by pressing q.

Create a file

Terminal

touch file.sh

touch creates files. man touch to learn more.

Check that file was created

Terminal

ls -a

You'll now see file.sh show up in the output.

Edit the file

Let's open VS Code in this directory so that we can edit the file.

Terminal

code -r .

The -r flag means re-use the same VS Code window if one exists. The . means this current directory.

Tip

Using lowercase letters and hyphens with no spaces for file and folder names will make script automation much easier.

code -r file.sh

You'll see the tab open in your VS Code.

Edit `file.sh`

Add the following:

file.sh

#!/bin/bash

This indicates to Linux/Unix that this is a bash script.

If you see a dot next to filename in the tab, that means it's not saved.

You can save the file with ⌘/Ctrl + S. Always ensure to save before moving on.

Check if `echo` works in the VS Code terminal

Terminal

echo "Hack the Tunnels"

You will then see the output:

Hack the Tunnels

It works, let's add it to the file.

file.sh

#!/bin/bash
echo "Hack the Tunnels" // [!code highlight]

Run the file

Terminal

./file.sh

You should see:

bash: permission denied: ./file.sh

Let's fix it by giving it permissions.

Terminal

sudo chmod +x ./file.sh

Run it again.

Terminal

./file.sh

You should see:

Hack the Tunnels

Make a cow say "Hack the Tunnels"

Terminal

brew install cowsay

Terminal

cowsay "Hack the Tunnels"

 __________________
< Hack the Tunnels >
 ------------------
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||

`fastfetch`, `cmatrix`, and `lolcat`

Rather than installing programs one by one, we can install multiple in a single command.

Terminal

brew install fastfetch cmatrix lolcat

When someone asks:

What are your specs?

We show them this.

Terminal

fastfetch

Output varies on your OS.

Fastfetch on MacOS

Very cool. Now, let's allow ourselves to feel like hackers.

Terminal

cmatrix

Press q to quit.

Now, let's allow ourselves to feel like hackers but in RGB.

Terminal

cmatrix | lolcat

Press q to quit.

Let's make a cow say "Hack the Tunnels".

Terminal

cowsay "Hack the Tunnels"

Let's make a cow say "Hack the Tunnels" but in a RGB.

Notes

You can hit the up arrow key on your keyboard to see past commands.

Terminal

cowsay "Hack the Tunnels" | lolcat

Change the text inside the quotes and try it a few more times to see what happens :)

Automate away

Notes

Any command you can run in the terminal, you can also write into the file and run.

Let's try cowsay.

file.sh

#!/bin/bash
echo "Hack the Tunnels"
cowsay "Hack the Tunnels" | lolcat // [!code highlight]

Let's spam cowsay because why not.

file.sh

#!/bin/bash
echo "Hack the Tunnels"
cowsay "Hack the Tunnels" | lolcat // [!code highlight]
cowsay "Hack the Tunnels" | lolcat // [!code highlight]
cowsay "Hack the Tunnels" | lolcat // [!code highlight]
cowsay "Hack the Tunnels" | lolcat // [!code highlight]
cowsay "Hack the Tunnels" | lolcat // [!code highlight]
cowsay "Hack the Tunnels" | lolcat // [!code highlight]

Save, and run the file again :)

Terminal

./file.sh

Bash commands review

Action	Command
Print 'Hello' to the terminal	`echo 'Hello'`
See your username	`whoami`
Print working directory	`pwd`
Create a directory	`mkdir your-directory-name`
Change into directory	`cd your-directory-name`
Go one directory back	`cd ..`
Remove directory	`rm -rf your-directory-name`
List contents of directory	`ls`
List contents of directory including hidden files	`ls -a`
Create file	`touch your-file-name`
Remove file	`rm your-file-name`

1. Automating cool things

Shell Navigation

See current location

See files in current location

Go to the home directory

Make a directory called `workspace`

Go into the `workspace` directory

Go into the `hack-the-tunnels-git-workshop` directory

Try the `echo` command

Create a file

Check that file was created

Edit the file

Make a Bash Script

Open VS Code terminal

Open `file.sh`

Edit `file.sh`

Check if `echo` works in the VS Code terminal

Make a cow say "Hack the Tunnels"

`fastfetch`, `cmatrix`, and `lolcat`

Automate away

Bash commands review

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1. Automating cool things

How do I go back one directory?

What happened there?

How did that work?

What does the `|` do?

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