ttytest - test if process connected to foreground terminal
is a routine to check if it is sensible to report messages to the standard
output. It returns 1 if the process is connected to a terminal and is
running in the foreground, and 0 otherwise.
To force detection of a terminal, set the environment variable GFORCE.
1.0 - Mark Huckvale
Fri Jul 09 14:54:20 2004