VMS Help DTM, SHOW, COLLECTION, Command Qualifiers, /OUTPUT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

   /OUTPUT[=file-specification]

   Sends the SHOW COLLECTION information to the specified file. If
   you specify the file name but omit the file type, the file type
   defaults to .LIS. The output is sent to SYS$OUTPUT.