syntax error: invalid arithmetic operator (error token is “.1.3.6.1.2.1.25.2.1.4

To fix this error I think there should be a space after /${storageName[$i]} in line 317 to prevent the grep for /volume1 also matching /volume10.

storageID[$i]=$(echo “$syno_diskspace” | grep “= “?/${storageName[$i]}”?” | cut -d “=” -f1 | rev | cut -d “.” -f1 | rev)