In my case I'll use "cat" instead of "wget" cause .html file is the output format of selenium result, so it's a "fake" webpage...
BTW, I'll study a bit more awk later, now my priority is to have it running.
So now, I have the number. I wrote a simple script to compare it with 3 threshold (nagios-style); my last doubt is:
The threshold now are fixed into the script, but AFAIK some other nagios check take advantage of $ARGS$ variables to set warning and critical level to custom values and it's more easy to modify (instead to edit the script I can simply edit these values, save the nagios check and then it grabs these values as the new threshold, leaving the script unmodified).
I'll check better on nagios-plugin documentation, but on a first quick view there was a lot of code to write...
the idea is something like:
"./check_selenium -w 70 -c 85 < file_with_number_found.txt"
Where, of course, -w is the warning threshold and -c is the critical one.
Thanks a lot for your help MensaWater