Function parse_args_or_exit 

pub fn parse_args_or_exit<T: TopLevelCommand>(help_style: &HelpStyle) -> T

Create a FromArgs type from the current process’s env::args_os() with the given HelpStyle. For the default help style argp::DEFAULT can be used.

This function will exit early from the current process if argument parsing was unsuccessful or if information like --help was requested. Error messages will be printed to stderr, and --help output to stdout.