if host pings execute command

[bash]#!/bin/sh
HOST="silveiraneto.net"
if ping -c 1 $HOST > /dev/null
then
echo your command
fi
[/bash]

• replace silveiraneto.net for your desired hostname or ip
• ping sends only one package (-c 1) and ignores the text output
• a ping is successful returns 0 and the if proceeds
• replace the echo line with your command