The Question is:
How can I update a message or progress bar in place on the screen from a DCL
without a line feed?
The Answer is :
Usually via generation of cursor-positioning sequences, or via the use
of escape sequences and the terminal's host status bar, or via the use
of escape sequences and DECterm title and icon labels (see the FAQ).
Which depends on what you are doing and on what support is available
within the particular terminal or terminal emulator that is used for
the application display.
Use of DCL for output will result in a carriage return and a line feed
at the end of the output string -- the positioning sequences can control
where on the display the output string will appear.