A macOS command line utility for listing listening TCP ports

lstcp 

That's it lol. The lsof utility which lstcp depends on requires admin privileges, so you will be prompted for your password on using this command if you have not provided it recently.

Using fisher:

fisher install jtrim777-dev/lstcp 

This plugin depends on americanhanko/fish-spin, which in turn depends on jorgebucaran/getopts.fish. If fisher decides to be mean and not install the transitive dependencies for your, you can install them manually with

fisher install jorgebucaran/getopts.fish americanhanko/fish-spin