lsof - list open files

Name     lsof - list open files 
Version  07/2000
Author   Shaun Tancheff 
Distrib. Freeware (?)
Type     EXE program (w/ source)
Price    -
Source   Internet 
         Name: lsof.* 

You can use lsof to find out if your REXX program opens files without 
closing them. 

You can also use the program psfiles.exe to get a list of open files 
(available in Warp 4 Fixpack 13) - but it's not as comfortable as lsof.