When a new Mac computer is purchased, an error is reported when the telnet command is used at the terminal: command not found: telnet. This is because telnet is not installed at the terminal.
Solution:
brew install telnet
If homebrew is not installed on the terminal, install homebrew first
/usr/bin/ruby -e “$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install )”
Then install telnet
brew install telnet