Add terminal upgrade

src/day_2/README.md

@@ -1,3 +1,6 @@
 # Day 2
 
-In this day, we will learn how to glue commands together to benefit from their modularity. Later, we will write our own shell scripts to achieve some automation.
+In this day, we will learn more about the terminal and how to glue commands together to benefit from their modularity.
+
+But we will start by making our terminal more comfortable!
+Let's make an upgrade away from the terminal of the 90s ✨

src/day_2/terminal_upgrade.md

@@ -0,0 +1,132 @@
+# Terminal upgrade
+
+## Fish
+
+When you run something in the terminal, then you are interacting with a so called _shell_.
+
+The default shell on almost all Linux systems is `bash`.
+Therefore, you should be familiar with it.
+
+But if you want a modern terminal experience instead of that of the 90s, then you should use the [Fish shell](https://fishshell.com/) 🐠
+The **f**riendly **i**nteractive **sh**ell".
+
+Bash offers basic (auto)completion, but Fish takes it to the next level!
+
+Type `ls ~/` (without hitting `Enter` yet) and press `Tab` twice in Bash.
+Bash will just show you all possible completion options.
+But Fish will let you cycle through these options with `Tab` and `Shift + Tab` to choose one!
+This doen't only work with paths, but also for commands and even command options!
+
+In Bash, you you can cycle through your command history using the up and down arrow keys.
+But in Fish, you can also start a command and _then_ cycle through your history that has the same **prefix** with the up and down arrow keys!
+
+It will also automatically give you suggestions to what you type based on history and completion!
+These autosuggestions are showed as dimmed text to the right of your input.
+To use that suggestion, you can just press the right arrow key (or `Ctrl + e`)!
+
+Fish also supports true color synatx highlighting 🌈
+
+Colors are not only fancy, but they can also be very helpful!
+If you start typing a command with a program that does not exit (like `echoo` instead of `echo` for example), Fish will highlight that program in red!
+Otherwise, the program is highlighted in blue!
+This gives you rapid feedback while typing 🤩
+
+You can also configure Fish in the file `~/.config/fish/config.fish`.
+Here is any example
+
+```bash
+if status is-interactive
+    # Disable the greeting message.
+    set -g fish_greeting
+
+    # Abbreviations
+
+    # Prevent overriding files/directories by accident when using `cp` and `mv`.
+    abbr -ag cp "cp -i"
+    abbr -ag mv "mv -i"
+    # Use `trash` by default instead of `rm`.
+    abbr -ag rm "trash"
+    # Use another shortcut for when you really want to delete instead of moving into a trash.
+    abbr -ag rmr "rm -r"
+    # Set some default options.
+    abbr -ag rsync "rsync -Lahz"
+
+    # Alias
+    # Use `bat` instead of `cat` for colored output!
+    alias cat "bat"
+
+    # Functions
+    function demo
+        echo "Hallo from the demo function!"
+        echo "Arguments taken: $argv"
+        echo "First argument: $argv[1]"
+    end
+    # Well will learn more about arguments later.
+end
+```
+
+Use **abbreviations** when you want your input to be replaced while typing with the ability to modify the replacement.
+**Aliases** should only be used if you are sure that the two commands are equivalent for you.
+
+## Zellij
+
+Now that we have a fancy shell, what can be even better than a fancy terminal?
+
+Multiple fancy terminals!
+
+Let me introduce you to [Zellij](https://zellij.dev/about/), a modern [terminal multiplexer](https://en.wikipedia.org/wiki/Terminal_multiplexer) written in Rust 🦀
+
+It offers panes, tabs and even floating panes!
+
+Start Zellij by running `zellij` and take a look at the shortcuts at the bottom.
+It is pretty user friendly!
+
+Press `Ctrl + p` to go into the _pane mode_ where you can select one of the shortcuts that newly appeared at the bottom.
+Press `n` in the _pane mode_ to create a **new pane**!
+
+You can change the focused pane by clicking on another pane.
+But there are also keyboard shortcuts for that.
+
+Normally, you can press `Ctrl + t` to go into the _tab mode_ where you can press `n` to create a new tab.
+But if you are using the terminal in the browser provided during the course, then you might not be able to press `Ctrl + t` without opening a _browser_ new tab.
+
+Therefore, we have to change that keybinding to something that does not conflict with the browser.
+To do so, create the directory `~/.config/zellij` and place the file `config.kdl` in it with the following content:
+
+```kdl
+keybinds {
+    normal {
+        bind "Ctrl b" { SwitchToMode "tab"; }
+    }
+}
+```
+
+This configuration uses the shortcut `Ctrl + b` instead of `Ctrl + t` to enter the _tab mode_.
+
+Now, use that new shortcut followed by `n` to create a new tab.
+The easiest way to change the focused tab is by clicking on the tab label at the top.
+But there are also keyboard shortcuts for that.
+
+Try detaching the session by pressing `Ctrl + o` followed by `d`.
+This will lead to exiting Zellij, but your session (open panes and tabs) is not gone!
+
+To attach back to that session, run `zellij attach` or `zellij a` for short.
+Fancy, right?
+You can just detach a session you working in, do something else and attach back to continue from where you have left it 😃
+
+There is still something annoying:
+Everytime you start zellij, you have to start fish afterwards.
+Wouldn't it be awesome to have Fish as the default shell in Zellij?
+
+Let's make it the default one!
+Add the following line to the beinning of the configuration file `~/.config/zellij/config.kdl`:
+
+```kdl
+default_shell "/usr/bin/fish"
+```
+
+You can check that this is the path of the program `fish` on your system by running `which fish`.
+
+We are not done with upgrading our terminal workspace.
+We will introduce more modern tools later.
+But this should be enough for now 🙂

src/day_3/notes.md

@@ -66,42 +66,6 @@ export PATH="$PATH:$HOME/.cargo/bin"
 alias rm="trash"
 ```
 
-## Fish
-
-`~/.config/fish/config.fish`
-
-```bash
-if status is-interactive
-    # Disable greeting message
-    set -g fish_greeting
-
-    # Abbreviations
-    abbr -ag cp "cp -i"
-    abbr -ag mv "mv -i"
-    abbr -ag rmr "rm -r"
-    abbr -ag rm "trash"
-    abbr -ag rsync "rsync -Lahz"
-
-    # Aliases
-    alias cat "bat"
-    alias lg "lazygit"
-
-    # Functions
-    function demo
-        echo "Hallo from demo function!"
-        echo "Arguments taken: $argv"
-        echo "First argument: $argv[1]"
-    end
-end
-```
-
-Add to path:
-
-```bash
-fish_add_path ~/.cargo/bin
-fish_add_path ~/.local/bin
-```
-
 ## SSH
 
 ### Setup host