How to stop the ping command if there is no reply after 1 sec?

Question

I'm writing a loop that checks whether a connection has been established.

I'm doing

ping -c 1 8.8.8.8
while [ $? -ne 0 ] do
  sleep 0.5
  ping -c 1 8.8.8.8
done

Now I'm not sure how this works, if the ping request got blocked on its way out (iptables or other) the command and the script will hang indefinitely. What I want is to stop waiting for a reply after 1 sec and send a new request. That until I get a reply faster than 1sec, the $? is equal to 0 and it breaks the loop.

does your ping have a `-W` option? Other OS's will have a `-w` for a timeout setting. — Jeff Schaller, Jul 27 '16 at 17:40
@JeffSchaller whichever contains the exit code, I think it's `$?` — ChiseledAbs, Jul 27 '16 at 17:40
Also consider http://serverfault.com/questions/200468/how-can-i-set-a-short-timeout-with-the-ping-command — kirkpatt, Jul 27 '16 at 17:42

score 3 · Accepted Answer · answered Jul 27 '16 at 17:46

3

while ! (ping -c 1 -W 1 8.8.8.8 > /dev/null); do
  sleep 1
done
echo "< 1 sec reply received...exiting"

answered Jul 27 '16 at 17:46

user1700494

2,172
8
13

that is a clean code, so basically in bash when you brace a command in parenthesis it outputs the exit code ? – ChiseledAbs Jul 27 '16 at 17:53

How to stop the ping command if there is no reply after 1 sec?

1 Answers1