tldr is a community effort to simplify command line utility man pages with useful examples. In addition to be hosted in a web client you can interact with tldr in the terminal using the tldr cli powered by node. Install it via npm:

npm install -g tldr

And use it by passing the command of interest as a paremeter to tldr:

tldr tmux

For more information about the tldr command line utility, the avavailable clients and how to contribute take a look at the tldr wiki.