to get any kind of useful answer, you will need to be a lot more specific.....
RedHat9--or any other Linux distro--is a collection of programs and utilities and library functions. Each on will have a defined response to various errors---some of which will be visible to the user and other not.
Just look at the common BASH commands---type in a few things like "find", "sed", or "grep" with some random syntax errors, and you will see a very small fraction of the possible error messages.
In your other threads, I assume someone has already told you that RH9 is very obsolete.