SUMMARY

I'm trying to implement some custom sensors for USB attached devices, but the examples floating around the internet no longer work. For instance, the simplified example perl sensor below will not run:

#!/usr/bin/perl -w

$! = 1;

print "ksysguardd 1.2.0\n";
print "ksysguardd> ";

while ( <> )
{
    if( /monitors/ )
    {
        print "random/speed\tinteger\n";
    }
    
    if( /speed/ )
    {
        if( /\?/ )
        {
            print "Random Speed\t0\t0\trpm\n";
        }
        else
        {
            my $val = int( rand()*100 );
            print  "$val\n";
        }   
    }
    
    print "ksysguardd> ";
}

1;


STEPS TO REPRODUCE
1. Save the above as a .pl file
2. On a new ksysguard tab, click file -> Monitor remote machine
3. Add in some name in host field (not necessarily a valid host name)
4. Select Custom command type
5. Enter the file from #1 as the command

OBSERVED RESULT

The host is shown in the sensor browser, but with a warning icon next to it and no sensor data. There is NO ERROR message indicating any failure. The process (random.pl) is running in the task manager, but doesn't seem to be executing anything.

EXPECTED RESULT

Custom sensor field available in sensor browser.


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: kubuntu 20.04 fully updated
(available in About System)
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.8

ADDITIONAL INFORMATION