Side question: How did the author create the PDF from the markdown source at https://github.com/nh2/strace-pipes-presentation/blob/master... ?
Not with strace, that's for sure.
He used a tool called Marp .
At the top of the Markdown file you can see a code that reads "page_number: true" which can be found in the sample file provided by Marp here . There are other tools out there that can be used to convert a Markdown into slides or PDF. I personally use Deckset.app  but searching "markdown presentation" — or — "markdown slides" on the Internet seems to bring a long list of projects aiming for the same feature set.
For example Pandoc which I personally enjoy
Do you write all your system scripts in Lua? How do you like it?
I like Lua for how thin and simple it is, with virtually no dependencies on anything. The good thing is that it runs anywhere where I have a C compiler, the bad thing is that it comes with no batteries included - there's not even a native function for creating a directory.
I use Lua a lot in my professional work as embedded software engineer, where the main business logic of the apps are written in Lua, with some thin C layers underneath for integration with various libraries and the OS.
Still, there are a lot of downsides to Lua, mostly the weak typing that bites me a lot. I'm slowly moving away from Lua to Nim these days, you should check that out if you haven't yet.