I have a minor problem which I'm guessing could be done with a regex. I am being sent a parameter from a CGI form that I need to check is valid.

What I need to check is that:

The string is exactly 4 characters long, not one more, not one less. It must only contain numbers and letters. Also, there is a high chance the string will arrive in lowercase and I need to convert it to uppercase before my script can use it.

I need to redirect the user to an error page if the string was invalid rather than continue running the script.

Can anyone help me with this one?

- Jed

In reply to String validation by Speedfreak

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