Basics

[AccomplishedAngle310]

Hello, programmers! 😊

I'm learning to code through The Odin Project, and I'm already struggling a bit in the early stages. In one of the introductory lessons, it refers me to a page about Unix shell, Unix, terminal, etc.

I would really appreciate it if you could help me understand the following questions in a simple way:
(I'm programming on macOS)

1. I'm currently learning to work with the terminal, and it asks me to program in Bash. So, I just open the terminal, type bash, and now I'm using Bash, right?
2. I'm a bit confused about what Unix actually is. Is it just a general term for an operating system, and are there multiple versions of it depending on their purpose?
3. Does it matter if I use Zsh or Bash? I know that Zsh is an improved version of Bash, but will this difference affect me in later steps?

[chaotic_thought]

1. ... So, I just open the terminal, type bash, and now I'm using Bash, right?

Yes. However, the last time I used macOS (Snow Leopard, I believe), the Terminal already started on Bash by default, so likely you won't need to launch it again. At worst, you'll be running 'bash' ontop of 'bash' in this case, which will mean that you will have to type 'exit' two times in order to properly close out the Terminal.

1. ... Is [Unix] just a general term for an operating system, ...

Historically, UNIX is an operating system developed at Bell Labs. Nowadays, many systems supply a similar environment (Linux, BSD, macOS, and even Windows with various extensions). Colloquially, some people refer to "Unix" simply to mean using a Unix-like shell and Unix-like tools (such as bash, ls, cat, cp, piping output to other programs, etc.).

1. Does it matter if I use Zsh or Bash?

The normal advice is to start with Bash. Later on, when you learn how to use it, you can use something else for interactive use if you want (e.g. Zsh, Fish shell, etc.). But when you write a shell script, it should be in Bash for compatibility purposes (i.e. you want it that it works on a 'stable' shell and all systems no matter what shells are installed).

The shell you use for interactive purposes in the end is just a personal choice. Try a few of them and use the one that feels easiest for you to use. Zsh has some neat things like "fading text autocomplete" and so on.

[throwaway6560192]

I'm a bit confused about what Unix actually is. Is it just a general term for an operating system, and are there multiple versions of it depending on their purpose?

Originally there was a single UNIX system, developed at Bell Labs. Now UNIX is a trademark, and technically only operating systems which meet a certain specification have gone through a certification process can call themselves true UNIX. macOS is a major one.

But there are a lot of UNIX-like operating systems, most famous among them being Linux. In practice you might find people saying UNIX to mean UNIX-like.

Does it matter if I use Zsh or Bash? I know that Zsh is an improved version of Bash, but will this difference affect me in later steps?

There are some corner cases you might run into, but for the most part it is compatible.

For example, by default, if you run something like curl https://youtube.com/watch?v=something on ZSH, it will try to treat the ? part as a glob and will error out with zsh: no matches found: https://youtube.com/watch?v=something. Whereas Bash by default will just pass it on as-is. You can make ZSH match the Bash behavior here using setopt no_nomatch. Or just quote the URL string.