Shell Programming and Scripting

Hi,

I'm writing scripts in perl and shell and want to add the oprion of
scrolling cursor on the screen when there is no output to the screen for long time. I saw it in some script but I don't have the source code.

Are anyone know how can I perform this ?

Thanks

There's simple and complex.

The simple method is to add a check for ever piece of code that might output data. But if you rely on a sub-process that might never return, this doesn't work too well.

The complex method is to set up a timer and trap the timer with something that outputs to the screen. The trap can check a variable before printing; that variable is reset every time there is output.

This demonstrates (in BASH) the basic concept:

Code:

wake_up() { 
echo "++ Waiting for more input ++" 
}

trap wake_up SIGALRM
( while true; do kill -SIGALRM $$; sleep 30; done ) &

date
sleep 90;
date
sleep 90;
date