control
(Or "ctrl", "^") One (or a pair) of {modifier
keys} found on all modern {keyboards}. If the control key is
held down while pressing and releasing certain other keys then
a "{control character}" is generated, e.g. holding control and
hitting "A" generates control-A ({ASCII} code 1). The ASCII
code for the control character is generally 64 less than that
for the unmodified character.
The control key does not generate any character on its own but
most modern keyboards and {operating systems} allow a program
to tell whether each of the individual keys on the keyboard
(including modifier keys) is pressed at any time.
Control characters mostly have some kind of "non-printing"
effect on the output such as ringing the bell (Control-G) or
advancing to the next line (Control-J). Most have alternative
names suggesting these functions (Bell, Line Feed, etc.).
See {ASCII character table}.
(1997-07-10)