Do you use shell-based version managers like nvm, pyenv, or rbenv, in combination with tmux on macOS? If so, you may be in for a surprise. Outside of tmux and screen, version managers will work fine, but inside the session, system or Homebrew installed tools will be used instead. What’s going on here?

In his wonderfully sarcastic lightning talk, Wat, Gary Bernhardt explores the dark side of Ruby and Javascript with examples that seem to defy logic. When I first saw Wat, I immediately wanted to know more. How do these strange behaviors come about? Is it an interpreter error, designed into the language, or something else entirely? If the behavior is intentional, what is the reasoning behind it? I decided to take the plunge and find out for myself.