Bash Exit Status codes for Ping

Question

I am working on a small script that checks if a host is up or down.

until [ "$STATUS" -eq "0" ]
do
ping -c 1 192.168.0.3
echo The host is down
STATUS=`echo $?`
done

It is supposed to change the status to 0 if it pings a host that is up and exit the until loop. But it doesnt. Even if I echo out the value of $? the value is always zero.

Can anyone help me figure this out please? :)

Thanks in advance

Answer 1

You have echo The host is down after ping command. So $? takes the exit status of the echo command not the ping command.

ping -c 1 192.168.0.3
STATUS=$?
if [ $STATUS -ne 0 ]; then
   echo "The host is down"
fi

Answer 2

You placed echo after saving the status that's why you always get 0:

ping -c 1 192.168.0.3
echo The host is down  ## Always changes $? to 0
STATUS=`echo $?`

One better way to do it could be:

until ping -c 1 192.168.0.3; do
    echo "The host is down"
done

Longer version:

until ping -c 1 192.168.0.3; STATUS=$?; [ "$STATUS" -eq "0" ]; do
    echo "The host is down"
done