How to segregate error types in brew?

[EmilyGraceSeville7cf]

Hello! I want to segregate error types in brew while installing new formulas:

• no internet connection
• smth is already installed

The problem root is that brew returns 1 in both cases. Perhaps I can use grep as workaround but I don't consider it as a good decision.

[SMillerDev]

You can check what's installed before you run the install by using brew ls formula