I wrote a warning shell script in vi, that is fully functional in Terminal.
So how do I configure Nagios (where and what), so this shell script will open, when a error shows up whe we get it in Service detalils some warnings/eroors/unknown etc?
or how do I get Nagios to open anything on the screen on the computer where Nagios is installed, for warning that something is wrong with a host or service.
If you want shell notification you could write shell script and put it as eventhandler. The shell script could use wall command to send the message to all currently logged users on your Linux machine.