Runs the CLI on argv (default process.argv) and returns the exit
status, which it also sets as process.exitCode: 0 on success (and for
--help/--version), 2 for a usage error (commander has already printed
it), 1 for any other error, printed as Error: <message>.
Runs the CLI on
argv(defaultprocess.argv) and returns the exit status, which it also sets asprocess.exitCode: 0 on success (and for--help/--version), 2 for a usage error (commander has already printed it), 1 for any other error, printed asError: <message>.