Ellane learns the command line

Case-sensitivity, ttys, and the prompt

Case-sensitivity #

Ellane
Question: is case important?

I didn't know you could do that thing with cd desktop. I find that a little weird and surprising.

Traditionally, *nix systems are case-sensitive.

Your Mac is not. It could be, but it isn't. There was a really good discussion on ATP recently: check episode 583 at 1:12:10.

Pretend like it is and you won't go far wrong.

ttys #

Ellane
One more question: what's ttys000?

When Terminals were the whole computer, they each had an ID. Just like your computer has a name.

When you launch a new Terminal window, it gets an identifier in the same way. Because you can launch another Terminal window, and be running commands in each.

Your system needs to know which command belongs to which window. So that's what ttys000 is.

Fun fact: ttys is short for teletyper secure. There's a great history lesson here -- this stuff goes back centuries.

We'll talk about this more later.

The prompt #

Ellane
And why the % sign? I seem to remember a $ sign being there last time.

This is just a style thing.

Until recently, the language that you were using in your Terminal was bash. The default 'prompt' for bash is $.

A couple of macOS versions ago they switched to zsh, which is more modern. Its default prompt is %.

The sh part of both of those is short for 'shell'. The original shell was just called sh! Wikipedia has a nice overview.

We won't use any zsh-specific stuff in this tutorial. And unless they say otherwise, all of the commands you'll find online that tell you how to install a thing will work in both shells.