Mac-20180529-telnetを離れた180日目、やっとそれを取り戻しました!

Problem

-bash: telnet: command not found
-bash: brew: command not found

Solution

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
brew install telnet

Reference
brew: command not found