The "sl" app found in Debian is just a "useless" (the sl's author's word, not mine) little app. It "trains" you to not misspell "ls" as "sl" by "punishing" you with an ASCII-art train that choo-choos its way across your terminal window. Written in the C programming language, it seemed the perfect little app to convert into Rust.
To see it in action, just install it with this command, typed in a terminal window by a sudo-capable user:
$ sudo apt update $ sudo apt install sl
And then run it with a simple:
$ sl
Whoo-hoo! Er, I mean, "Whoo-whoo!"
You can even throw some options to the program, such as:
$ sl -F
which causes the train to "F"ly.
or:
$ sl -a
which results in an apparent "a"ccident.
or:
$ sl -l
which draws a "l"ittle train instead of the standard D51 train.
To see the man page ("manual") for "sl", just:
$ man sl
What we'll be doing is converting the human-readable source code for this program from the C programming language to the Rust programming language. To continue, we'll need to make sure that we have a working Rust environment on your Debian box. We'll do this in the next lesson, Establish a Working Rust Environment.