Slightly related is https://cheat.sh/ [0], which returns real-world examples of how to use a given command.

The results are nicely formatted and color-coded. Give it a try in your terminal:

  curl https://cheat.sh/rsync

I've found it to be really handy for things like awk, rsync, ssh, and others with byzantine parameters. Not to mention it's free.

[0] https://github.com/chubin/cheat.sh

tldr.sh is a similar project.

https://github.com/tldr-pages/tldr