Homebrew cask option not recognized?

Question

I am following an online resource for installing two Mac utilities

http://www.economyofeffort.com/2014/08/11/beyond-ctrl-remap-make-that-caps-lock-key-useful/

Here is the pertinent section:

Install both Karabiner and Seil. (Here again, if you use Homebrew Cask, you can do this with

$ brew cask install karabiner and

$ brew cask install seil

But the cask option is not recognized?

06:51:35/shared $brew cask install seil
Error: Unknown command: cask

Then, just for laughs I tried the command without the cask:

06:55:01/shared $brew install seil
Error: No available formula for seil
Searching formulae...
Searching taps...
Caskroom/cask/seil

It is not clear what the last line of output even means: nothing seems to have happened on the system.

I am on Yosemite.

Answer 1

To use brew cask you should have it installed, this is a extension of brew, is not native.

To install it you need to run brew install caskroom/cask/brew-cask from your command line

Homebrew Cask homepage or Homebrew Cask Github

Answer 2

brew tap caskroom/cask

brew install brew-cask

Now, you are ready to brew cask.

Answer 3

You can also just brew install Caskroom/cask/seil. It will automatically tap the correct cask for you :)

Answer 4

One other thing to check is that it may be installed but not linked:

$ brew install caskroom/cask/brew-cask
Warning: caskroom/cask/brew-cask-0.59.0 already installed, it's just not linked

This is easily fixed by running:

$ brew link brew-cask