Crontab in skripta v 8.04.2; kako?

Imam neko skripto, ki gleda network activity na strežniku in po določeni neaktivnosti ugasne strežnik z ukazom sudo /sbin/shutdown -h now. Vendar mi nikakor ne uspe omenjene skripte zagnati s cron-om oz crontab-om.
Crond se zažene ob boot-u, v /var/log/syslog je viden potek CRON. Vnos je dodan v cron z ukazom crontab -e.
Uporabniku je dovoljeno v sudo visudo pognati /sbin/shutdown brez gesla.
Kaj bi bilo lahko narobe?
LP

Torej, skripta off.sh:

#!/bin/bash (oz. /bin/sh)
#
# This is scheduled in CRON. It will run every 20 minutes
# and check for inactivity. It compares the RX and TX packets
# from 20 minutes ago to detect if they significantly increased.
# If they haven't, it will force the system to sleep.
#

log=~/Scripts/idle/log

# Extract the RX/TX
rx=`/sbin/ifconfig eth0 | grep -m 1 RX | cut -d: -f2 | sed 's/ //g' | sed 's/errors//g'`
tx=`/sbin/ifconfig eth0 | grep -m 1 TX | cut -d: -f2 | sed 's/ //g' | sed 's/errors//g'`

#Write Date to log
date >> $log
echo "Current Values" >> $log
echo "rx: "$rx >> $log
echo "tx: "$tx >> $log

# Check if RX/TX Files Exist
if [ -f ~/Scripts/idle/rx ] || [ -f ~Scripts/idle/tx ]; then
p_rx=`cat ~/Scripts/idle/rx` ## store previous rx value in p_rx
p_tx=`cat ~/Scripts/idle/tx` ## store previous tx value in p_tx

echo "Previous Values" >> $log
echo "p_rx: "$p_rx >> $log
echo "t_rx: "$p_tx >> $log

echo $rx > ~/Scripts/idle/rx ## Write packets to RX file
echo $tx > ~/Scripts/idle/tx ## Write packets to TX file

# Calculate threshold limit
t_rx=`expr $p_rx + 1000`
t_tx=`expr $p_tx + 1000`

echo "Threshold Values" >> $log
echo "t_rx: "$t_rx >> $log
echo "t_tx: "$t_tx >> $log
echo " " >> $log

if [ $rx -le $t_rx ] || [ $tx -le $t_tx ]; then ## If network packets have not changed that much
echo "Shutdown ..." >> $log
echo " " >> $log
rm ~/Scripts/idle/rx
rm ~/Scripts/idle/tx
sudo /sbin/shutdown -h now ## Shutdown
fi

#Check if RX/TX Files Doesn't Exist
else
echo $rx > ~/Scripts/idle/rx ## Write packets to file
echo $tx > ~/Scripts/idle/tx
echo " " >> $log
fi

cron ukaz:

*/20 * * * * /home/user/off.sh

off.sh je executable

sudo rabim zaradi samega ukaza, ki se mora izvršiti brez gesla (ALL= NOPASSWD)

že, ampak stvar se mora izvršiti brez gesla...

Da.

da ne odpiram nove teme...

nastavil sem crontab, ampak ni nobenega efekta...

crontab -l kaže sledeče:

# m h  dom mon dow   command
30 21 * * sun,mon,tue,wed,thu iptables -A FORWARD -s 192.168.0.11 -j DROP
0 23 * * fri,sat iptables -A FORWARD -s 192.168.0.11 -j DROP
0 4 * * * iptables -D FORWARD -s 192.168.0.11 -j DROP

to sem naredil kot root, se pravi sudo su