- A friend got an error message when trying to use `brew extract` and it
wasn't immediately obvious to me why. The usage banner only mentioned
the "formula" argument, which they'd provided. This improves the error
message when there aren't enough arguments so that others have a
chance of figuring out how to use this command without having to look
at the code for `extract_args`.
Before:
```
➜ brew extract --version='1.4' libftdi
Usage: brew extract [--version=] [--force] formula ...
[...]
Error: Invalid usage: this command requires a formula argument
```
After:
```
➜ brew extract --version='1.4' libftdi
Usage: brew extract [options] formula tap
[...]
Error: Invalid usage: This command requires at least 2 named arguments.
```
- I don't like the "at least 2" phrasing here but that's a dive into the
arg parsing code that I don't have time for right now. An alternative
was `named_args [:formula, :destination_tap]`, but that gave the error
message "requires formula or destination_tap" which wasn't great
either. I also tried `min: 2, max: 2` and that was the same "at least
2" message.
49b9b6cf3f