Abort if earlygetopt fails to detect an option.
Otherwise it could happen that a command is used on the wrong repository,
because abbreviations of --cwd or --repository were ignored.
Is there an error message when trying to diff non-existing files?
found: No such file or directory
not: No such file or directory
Is there an error message when trying to add non-existing files?
found: No such file or directory
not: No such file or directory