index: add goal and presentation of cli

1 files changed, 49 insertions, 12 deletions

diff --git a/index.md b/index.md
index bd6fffb..c2a7141 100644
--- a/index.md
+++ b/index.md
@@ -1,11 +1,10 @@
 % WTF is Linux
 
+
 > What I cannot create, I do not understand.
 >
 > --- <cite>Richard Feynman, 1988</cite>
 
-TODO: add the LM fonts referenced in the CSS
-
 TODO: reference a mono font in the CSS
 
 TODO: fix TOC CSS
@@ -18,12 +17,58 @@ TODO: specify dependencies
 
 TODO: Add a plan checklist?
 
-TODO: fix pandoc\'s vimwiki (syntax highlighting, quotes)
-
 TODO: Link manpages
 
 TODO: Add pretty pictures
 
+Goal of this course and this document
+-------------------------------------
+
+In this course, we will attempt to create a GNU/Linux file system from scratch.
+
+The objective is to deeply understand the Linux ecosystem: how it boots, what
+are the different pieces, how do they integrate with one-another, what are the
+different choices available to us when building such a system, etc.
+
+Even though it is very rare to build these kinds of things "manually", I do
+think it is better to do it this way for educative purposes.
+
+However, in the practical work part, we will build a Linux system in an
+automated fashion, using [Buildroot](https://buildroot.org/), an well-known
+software in the industry for building embedded Linux systems.
+
+This document is intended to serve several functions:
+
+- As notes, if I talk too fast, or if you don't like to take
+  notes[^take-notes], or miss classes
+- It's likely that this website is going to be more detailed than the course,
+  so it's useful you want to go further. You can also follow the links to go
+  even further
+- Should I miss some things while talking, this website should fix it
+
+[^take-notes]:
+        {-} You really should be taking notes, it does help remembering
+
+The Linux command-line
+----------------------
+
+Main article: [CLI](cli.md)
+
+When we say "command-line interface", we usually mean the text-based program
+whose main purpose is to execute other commands. You input a program name, enter
+its arguments, press enter, and it will execute the said program with said
+arguments.
+
+In reality, the UNIX command-line is more complicated than that, but that also
+makes it much more powerful. See the main article if you want to unlocking this
+power.
+
+<!--
+A shell is a programming language whose main goal is to launch other
+programs. It also usually provides a command-line interpreter: a text-based
+program that executes (interprets) the shell code you input.
+-->
+
 The Linux Kernel
 ----------------
 
@@ -62,14 +107,6 @@ first program launched it always has a PID of 1.
 
 TODO: link to first steps to "user-space booting"
 
-The Shell
----------
-
-TODO: link to main article
-
-A shell is a programming language whose main goal is to launch other
-programs.
-
 Special filesystems
 -------------------