$ demo --help
clap [..]
A simple to use, efficient, and full-featured Command Line Argument Parser

USAGE:
    demo[EXE] [OPTIONS] --name <NAME>

OPTIONS:
    -c, --count <COUNT>    Number of times to greet [default: 1]
    -h, --help             Print help information
    -n, --name <NAME>      Name of the person to greet
    -V, --version          Print version information

$ demo --name Me
Hello Me!

(version number and .exe extension on windows replaced by placeholders)