Q: Does anyone know if it's possible to check for an open database file in CL? For example, I only want to execute the Close File (CLOF) command if the file is open.

A: The most straightforward way to do this is to execute the CLOF command for the file unconditionally and monitor for message CPF4520-"No file open with identifier [file]." Don't take any action if the error message is received- simply ignore it and continue.