Thank you all for the help.
Yes, the check is now found.
But it appears to be just a static Check with no script output. The output of the script on the monitored host which should monitor the total disk usage accross all disks is not there.
It just looks like this:
But the intention of the check was to monitor the output of and a statistic of that. The percentage is not needed.
It should be similar to the integrated Filesystem check, but just the total usage in TB
The output of df -h --output=size --total | awk 'END {print $1}’ in the command line is:
1,5T
So the intention was to create a check which outputs this 1,5T and has a statistic of that, where you can see the fluctuation in used space of the disk usage in TB.