Sends TCP Pakets to the TCP Server. Turns on lights if Computer is reachable, off if not reachable. lights_state.sh syncs the states of the lights, so the lights are turned on on next day. Avoids turning off or on if you manually turned on or off the lights.Used with crontab.

lights.sh

#!/bin/bash
/usr/local/bin/ping -c 1 192.168.1.2
ec=$?

state=`cat /root/light2_state`
stat=`echo -e "licht 2 status" | nc 192.168.1.3 54321`
s=$((${#stat}-1))
stat=${stat:$s:1}
echo "nc: $stat"
echo "file: $state"
if [ "$stat" -eq "$state" ]; then
    if [ $ec -eq 0 ]; then
        echo -e "licht 2 an" | nc 192.168.1.3 54321
        echo "1" > /root/light2_state
    else
        echo -e "licht 2 aus" | nc 192.168.1.3 54321
        echo "0" > /root/light2_state
    fi
fi

state=`cat /root/light3_state`
stat=`echo -e "licht 3 status" | nc 192.168.1.3 54321`
s=$((${#stat}-1))
stat=${stat:$s:1}
echo "nc: $stat"
echo "file: $state"
if [ "$stat" == "$state" ]; then
    if [ $ec -eq 0 ]; then
        echo -e "licht 3 an" | nc 192.168.1.3 54321
        echo "1" > /root/light3_state
    else
        echo -e "licht 3 aus" | nc 192.168.1.3 54321
        echo "0" > /root/light3_state
    fi
fi

lights_state.sh

#!/bin/bash
state2=`echo -e "licht 2 status" | nc 192.168.1.3 54321`
state3=`echo -e "licht 3 status" | nc 192.168.1.3 54321`

s2=$((${#state2}-1))
s3=$((${#state3}-1))

echo ${state2:$s2:1} > /root/light2_state
echo ${state3:$s3:1} > /root/light3_state

z crontab

59 18  * * *    /root/lights_state.sh
*/10 0-2,19-23  * * *    /root/lights.sh