Old IRC client based chatrooms.

[Baseplate]

Hey so I have honestly never used a IRC client but I have seen it in several videos. I find it interesting and the whole old tech Linux based CLI interface sells it for me. Are they still in use?

[Memory]

IRC has been in use for decades and it still is, not just by niche communities but by the general public. I use IRC daily, and so do tens or hundreds of thousands of others. Many software projects are only on IRC. It's all but dead.

The biggest network currently is Libera.Chat, which is centered around free software, but there are also some others. Wikipedia has a list of major IRC networks if you want to look up some smaller ones (but beware, not all of them are good natured and since IRC is not anonymous, there may be problems).
It's anything but abandoned, I can chat with 700+ people right now in ##chat.

I don't quite know what you mean by 'Linux based CLI interface'. There are probably hundreds of IRC clients for every operating system ranging from full graphical goodness with dozens of menus and helper scripts to the simple TUI programs you're likely referring to.

IRC is pretty in-depth these days when it comes to features like NickServ, so the GUIs are likely worth it. TUIs like irssi take some learning.

I recommend visiting Libera.chat (as in the website) and familiarizing yourself with the how-to's; they teach you about IRC and its concepts and how to connect with Libera Chat itself.

[Baseplate]

How safe are IRC's for example If I want to install WEEchat to my linux system, do I need to do any additional tasks?

[Memory]

How safe are IRC's for example If I want to install WEEchat to my linux system, do I need to do any additional tasks?

Generally, it depends on what your definition of "safe" is.

IRC is not anonymous. Anyone who is in the same IRC as you knows your public IP address and could theoretically find out some information about you through that. There are often ways to hide it visually, but anyone who cares enough could still find out where you live. People just don't do that though as they have better things to do and just want to talk about tech.

Encrypting your traffic via SSL/TLS is a good idea and is supported by default by Libera.Chat. This protects your conversation with the others from third parties like your internet provider, not from the others.

If you use WeeChat, the Arch wiki has a good two-line tutorial on how to correctly use SSL here:
https://wiki.archlinux.org/title/WeeChat#Configuring_SSL

Other than that, you don't really need to do anything. Register your nick via NickServ so nobody else can impersonate you, maybe think about masking your IP, both of which you can find out how to do on Libera.Chat.