pub fn test_subcommand(
    matches: &ArgMatches,
    command: Command
) -> Option<Result<(), String>>
Expand description

Check the [ArgMatches] for the subcommand added by add_subcommand.

All printing is done to stderr to avoid clogging up potential output.


Ignore if this returns None. Exit application when this returns Some, and signal the user with the error, if any.