Mac安装chromedriver和geckodriver

DY@MacBook-Pro bin$brew install chromedriver
Error: No available formula with the name "chromedriver"
It was migrated from homebrew/core to homebrew/cask.
You can access it again by running:
brew tap homebrew/cask
And then you can install it by running:
brew cask install chromedriver
DY@MacBook-Pro bin$brew cask install chromedriver
==> Tapping homebrew/cask
Cloning into '/usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask'...
remote: Enumerating objects: 4175, done.
remote: Counting objects: 100% (4175/4175), done.
remote: Compressing objects: 100% (4153/4153), done.
remote: Total 4175 (delta 27), reused 760 (delta 19), pack-reused 0
Receiving objects: 100% (4175/4175), 1.33 MiB | 816.00 KiB/s, done.
Resolving deltas: 100% (27/27), done.
Tapped 1 command and 4077 casks (4,185 files, 4.2MB).
==> Satisfying dependencies
==> Downloading https://chromedriver.storage.googleapis.com/2.44/chromedriver_ma
######################################################################## 100.0%
==> Verifying SHA-256 checksum for Cask 'chromedriver'.
==> Installing Cask chromedriver
==> Creating Caskroom at /usr/local/Caskroom
==> We'll set permissions properly so we won't need sudo in the future.
Password:
Sorry, try again.
Password:
==> Linking Binary 'chromedriver' to '/usr/local/bin/chromedriver'.
🍺  chromedriver was successfully installed!
DY@MacBook-Pro bin$brew install geckodriver
Updating Homebrew...
==> Auto-updated Homebrew!
Updated 1 tap (homebrew/core).
==> Updated Formulae
libbladerf

==> Downloading https://homebrew.bintray.com/bottles/geckodriver-0.23.0.high_sierra.bottle.tar.gz
######################################################################## 100.0%
==> Pouring geckodriver-0.23.0.high_sierra.bottle.tar.gz
🍺  /usr/local/Cellar/geckodriver/0.23.0: 7 files, 6.7MB