Keyboard input Buffer

[Rick Stevens]

karlp at ourldsfamily.com wrote:
> In other languages, I can read the keyboard buffer and test for input. Is
> there any command/sh function that will allow for such behavior from
> within a shell script?
> 
> I'm envisioning something like:
> 
> for i in `ls /dev/tty*`
> do
> something or other
> KEYIN=`check keyboard buffer prg`
>  if [ "$KEYIN" ! '' ] ; then
>    :
>  else
>    do something else
>  fi

You can't "peek" at the keyboard buffer without reading it in bash.
However, you could:

for i in `ls /dev/tty`; do
     something
     read -t 1 TEST
     if [ "foo$TEST" = "foo" ]; then
	nothing was typed in in the last second
     else
	something was typed in, but it's in $TEST now, not the buffer
     fi
done

The value after the "-t" in the read command sets the timeout in
seconds.  You'll be responsible for putting the buffer back together
if you need the data later.
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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
- Linux is like a wigwam...no windows, no gates...and apache inside! -
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