Почему NetHogs сообщать 0 КБ / сек при тестировании lo?

Возможно что-то вроде

#!/bin/sh
MatchLabel=Backup
CheckPath=/mnt/usb0

realDevice=`readlink -f /dev/disk/by-label/$MatchLabel 2>/dev/null`
mountedDevice=`awk "/ $CheckPath /{print \$1}" /etc/mtab 2>/dev/null`
test "$mountedDevice" && realMountedDevice=`readlink -f $mountedDevice`

if test "$realDevice" = "$realMountedDevice"; then
    echo $MatchLabel mounted to $CheckPath
else
    echo $realMountedDevice was unexpectedly mounted to $CheckPath
fi