DDOWN
DNEXT
DUP

Syntax: DDOWN subdirectory
   and: DNEXT subdirectory
   and: DUP
Location: Toolkit II 

DDOWN adds the specified subdirectory to the default data device as a suffix. If the default program device is the same as the default data device, thenthis will also be altered by DDOWN. If the default destination device is a directory device (ie. if it ends with an underscore), DDOWN also alters this (whether or not it points to another drive).

DNEXT allows you to move across a directory tree - the current sub-directory is replaced by the new parameter in the default data device.  DNEXT will also alter the default program directory (if this is the same as the default data directory) and the default destination device if it is a directory device.

DUP strips off the last sub-directory from the default data device, program device and destination device if the same rules as for DNEXT are met.

NOTE:
The default devices cannot exceed 32 characters (plus a final underscore) - any attempt to extend them beyond this will result in the error 'Bad Parameter' (error -15).

CROSS-REFERENCE:
DATAD$ and DLIST can be used to find out about the current sub-directory and default devices respectively.
