mjhjmtu

I'm trying to diagnose network instability on my home LAN -- I'm losing connectivity between my router and my cable modem. In my shell script, I'd like to ping the first ip address past the modem, and return false when that fails, so that I can trigger other actions in my script.

Does anyone know of such a beast?

Yes, it is called ping.

Try something like this (in bash):

while true ; do 
 if ping -c 1 10.202.15.54 > /dev/null ; then 
 echo "It works"
 else 
 echo "It does not work"
 fi
 sleep 5
done

ping -c 1 $my_host > /dev/null ; if [ $? -eq 0 ]; then "echo all good";else "echo error"

I'd do this, you'd get a log so you could run it over time and graph the result in excel.

#!/bin/bash
#Script to ping the IP after the gateway. 

LOG="ping.csv"
TARGET="10.0.0.1"

while :
do
 if `ping -c1 $TARGET > /dev/null ` 
 then
 STATUS="OK"
 else 
 STATUS="FAIL"
 fi

 echo "`date +'%D %H:%M:%S'` : $STATUS "
 echo "`date +'%D %H:%M:%S'` , $STATUS " >> $LOG
 sleep 30
done

Pretty simple:

$ ping -c 1 -W 3 www.go.org | grep -q "100% packet loss" && echo "Packet loss" || echo "Packet received"