Etherwake in a script works when executed in a shell but no in in cron

[aconsuegra2]

I am configuring a backup in ubuntu server.
It consists in a second server, powered by POE (etherwake command) in the backup script.
When i execute the script, as root in a ssh shell session, the backup server is powered on as expected, but if i program a job in crontab, the etherwake commnad does nor power up backup server.
Everithing in the backup script works just as expected, except the etherwake command.
If i execute the etherwake command in another ssh session, the backup ends ok.
The crontab job is added in the root account (executed as root)

Relevant parts of script home-sync.sh

#!/bin/bash
#
TYPE="sync"
HOST="prodsvr"
LOGFILE="/home/copias/bck$TYPE`date +%y%m%d`.log"
SOURCE="/home/"
DESTDIR="/home/copias/home"
DESTHOST="bcksvr"
DESTPH="00:10:a1:f0:01:c0"
WAIT=1
BCKBOOT=0
echo `date`: Iniciada copia a sistema de respaldo > $LOGFILE
while [ $WAIT -le 15 ]
do
        PING=$(ping -c 1 $DESTHOST 2>&1| grep "% packet" | cut -d" " -f 6 | tr -d "%")
        if [ "$PING" = 0 ]
                then
                        echo `date`: $DESTHOST está vivo >> $LOGFILE
                        WAIT=15
                        BCKBOOT=1
                else
                        echo `date`: Despertando $DESTHOST pase $WAIT >> $LOGFILE
                        etherwake $DESTPH
                        sleep 1m
        fi
        (( WAIT++ ))
done
.
.
.

And the contab line in root accout:

00 02 * * * /home/copias/home-sync.sh

How is it possible?

[steeldriver]

Hello and welcome to the forums

Where is the etherwake command located? it may be in your path, but not in cron's path. It's good practice to use absolute paths for all commands in cronjobs just to be sure.

[CharlesA]

Use the full path.

I don't use etherwake, I use wakeonlan in my script.

#!/bin/bash

# Path variables
ping=/bin/ping
rsync=/usr/bin/rsync
wakeonlan=/usr/bin/wakeonlan
grep=/bin/grep
ssh=/usr/bin/ssh
mail=/usr/bin/mail
date=/bin/date

# rsync/ssh variables
source=/array/.
destination=/backup/
user=root
host=loki

# Email variable
email=user@domain
longdate=$($date +%D)

# counter variables
i=1
timeout=120

# Get Date/Time backup started
startdate=$($date +%D)
starttime=$($date +%T)
start=$($date +%s)


# Check to see if host is up, and if it isn't send magic packet
if [[ -z $($ping -c 1 -W 1 $host | $grep icmp_req=1)  ]];
then
        $wakeonlan 00:23:54:47:94:4f
else
        echo "Host is already up"
fi
# Wait until $timeout to make sure host is up.
while [[ -z $($ping -c 1 -W 1 $host | $grep icmp_req=1) ]];
do
        sleep 1 && echo $i
        if [[ $i = $timeout ]]; then break
        fi
i=$((i +1))
done

if [[ $i = $timeout ]];
then
        echo "$host not up after $timeout seconds!" | $mail -s "$host not up to sync to!" $email; exit 1
else
# Wait 15 seconds to make sure ssh is running and machine is fully booted
        echo "Host is up, waiting 15 seconds to make sure ssh is running..." && sleep 15 && echo "Running rsync..." &&  $rsync --archive --itemize-changes --delete --exclude lost+found $source $user@$host:$destination

# Get Date/Time backup completed
stopdate=$($date +%D)
stoptime=$($date +%T)
end=$($date +%s)

fi
if [[ $? -ne 0 ]];
then
        echo "Rsync encountered an error!" | $mail -s "Sync with $host failed!" $email && $ssh $user@$host 'shutdown -h -P now'
else
        $ssh $user@$host 'shutdown -h -P now'
fi

# Send email of success
(echo "Backup started at:  $startdate  $starttime" && echo "Backup finished at: $stopdate  $stoptime" && echo && echo "Duration in seconds: $(($end-$start))") | $mail -s "Sync to Loki complete for $longdate" $email

[aconsuegra2]

outch....Thanks to both charlesa and steeldriver. A newbie fail....
I have added at the begining:

GREP="$(which grep)"
PING="$(which ping)"
WAKE="$(which wakeonlan)"
#WAKE="$(which etherwake)"
SLEEP="$(which sleep)"
MAIL="$(which mail)"
SSH="$(which ssh)"
CUT="$(which cut)"
TR="$(which tr)"
MAIL="$(which mail)"

This make the script moore portable in other systems.

BTW, etherwake does not work in crontab, even with full path to binary. I have used wakeonlan (thx again charlesa) but i have to add -i option: "wakeonlan -i [net broadcast addr] [physical addr]"
Everithing is now working as expected.