How to read the keyboard when stdin redirected

[Darren Drapkin via Digitalmars-d-learn]

As part of a course on Computing, I am trying to create a cut 
down version of GNU _more_.  I need it to read the keyboard when 
stdin is redirected at the end of a pipeline. This happens when 
_more_ outputs a screen full and prompts the user to scroll the 
screen.
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Yours &c.
Darren Drapkin