问一个关于用 Brew 安装 mtr 时的问题

个人用的zsh，按照网上的步骤用brew安装mtr

~ brew install mtr
==> Downloading https://homebrew.bintray.com/bottles/mtr-0.86.yosemite.bottle.ta
Already downloaded: /Library/Caches/Homebrew/mtr-0.86.yosemite.bottle.tar.gz
==> Pouring mtr-0.86.yosemite.bottle.tar.gz
==> Caveats
mtr requires root privileges so you will need to run `sudo mtr`.
You should be certain that you trust any software you grant root privileges.
==> Summary
/usr/local/Cellar/mtr/0.86: 8 files, 148K
~ sudo mtr google.com
sudo: mtr: command not found
~ mtr google.com
zsh: command not found: mtr
~

唔. 即便按照提示加了sudo，也无法运行mtr