Returns a tuple. First value is true if command line arguments were successfully
processed and execution should continue, or false if an error occurred or the user
asked for help. If false, the second value is the appropriate exit code (0 or 1).
Returning true (execution continues) means args have been validated and derived
values calculated. In addition, field indices have been converted to zero-based.
If the whole line is the key, the individual fields list will be cleared.
Command line argument processing.
Returns a tuple. First value is true if command line arguments were successfully processed and execution should continue, or false if an error occurred or the user asked for help. If false, the second value is the appropriate exit code (0 or 1).
Returning true (execution continues) means args have been validated and derived values calculated. In addition, field indices have been converted to zero-based. If the whole line is the key, the individual fields list will be cleared.