Linux Ping: Show time out

fping did not work for me... In my case, most of the time I want to see this is basically during server rebooting... this works pretty nice on Windows...

I build a simple script (expanding @entropo answer) to help me on that, which may help answering this question:

https://gist.github.com/brunobraga/7259197

#!/bin/bash

host=$1

if [ -z $host ]; then
    echo "Usage: `basename $0` [HOST]"
    exit 1
fi

while :; do
    result=`ping -W 1 -c 1 $host | grep 'bytes from '`
    if [ $? -gt 0 ]; then
        echo -e "`date +'%Y/%m/%d %H:%M:%S'` - host $host is \033[0;31mdown\033[0m"
    else
         echo -e "`date +'%Y/%m/%d %H:%M:%S'` - host $host is \033[0;32mok\033[0m -`echo $result | cut -d ':' -f 2`"
        sleep 1 # avoid ping rain
    fi
done

And usage is something like:

The best thing I found was to use the -O flag (Note that it does not work on all distros - using Linux Mint 17.1 Rebecca IPUTILS-PING 3:20121221-4ubuntu1.1)

$ ping -O 10.10.5.1

64 bytes from 10.10.5.1: icmp_seq=53 ttl=245 time=460 ms
no answer yet for icmp_seq=54
64 bytes from 10.10.5.1: icmp_seq=55 ttl=245 time=265 ms
64 bytes from 10.10.5.1: icmp_seq=56 ttl=245 time=480 ms
no answer yet for icmp_seq=57
64 bytes from 10.10.5.1: icmp_seq=58 ttl=245 time=348 ms
64 bytes from 10.10.5.1: icmp_seq=59 ttl=245 time=515 ms
no answer yet for icmp_seq=60
64 bytes from 10.10.5.1: icmp_seq=61 ttl=245 time=320 ms
64 bytes from 10.10.5.1: icmp_seq=62 ttl=245 time=537 ms

From the man page:

-O Report outstanding ICMP ECHO reply before sending next packet. This is useful together with the timestamp -D to log output to a diagnostic file and search for missing answers.

When I use ping to see if a host is up in shell scripts, I do something like this:

ping -W 1 -c 1 $HOST 2>&1 > /dev/null || (echo -n "dead!"; false) && command-that-needs-host-to-be-up

Basically, sends one ICMP that times out in a second with no output and uses the exit code to gate further action.

There's no way for the common ping to do that. If you are trying to script something you have some options:

ping -c 2 <ip>
RESULT=$?
echo $RESULT
1

If the ping fails, $? will be 1, if the ping is successful, $? will be 0.

The other option is using fping that works a lot like Cisco ping:

$ fping 200.1.1.1
200.1.1.1 is unreachable
$ fping 192.168.1.1
192.168.1.1 is alive