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# Formatting of socket

IRC is quite a hassle to understand, so the first thing to know about the protocol is the **socket** and **server/client**.

It's quite simple on client-side, but server-side has to supply more info:

```
↗️ PRIVMSG foo :content
🔀 :nick!ident@host PRIVMSG foo :content
↗️ COMMAND arg :content
↙️ :server RPL nick data :content
```

> [!CAUTION]
> If the command has content, the colon MUST be included, and is at the beginning of the content, not the end of the command/args.
> ```
> ↗️ COMMAND: content
> ↙️ :server 421 nick COMMAND: :Unknown command
> ```
> For more info on colon prefixes, see [Colon Prefixing](prefixing.md)  
> For more info on error 421, see [Unknown Command](notfound.md)