I have attached the script. It is extremely basic, but you can build on it very easily. Actually, if you are familiar with Informix, they have a built-in tool called dbschema...that's where i got the name from. I'm going to try to mimic the tool as much possible as it's been one of the best command line tools I have ever used for dumping schemas.

You can see the full usage here: http://publib.boulder.ibm.com/infocenter/idshelp/v10/index.jsp?topic=/com.ibm.mig.doc/mig170.htm