fast ping

# `pg` with no arguments ping the IP 8.8.8.8 (usefull for basic internet connection test), 
# otherwise ping the given IP. If the IP is incomplete, it is concat with the default 
# prefix 192.168.1 allowing easy local ping (eg ping 3.12 => 192.168.3.12)
function pg() {
	ip4regex='^[0-9]+[.][0-9]+[.][0-9]+[.][0-9]+$'
	ip3regex='^[0-9]+[.][0-9]+[.][0-9]+$'
	ip2regex='^[0-9]+[.][0-9]+$'
	ip1regex='^[0-9]+$'
	host=$@
	if [[ $# == 0 ]]; then
		host="8.8.8.8"
	elif [[ $@ =~ $ip4regex ]]; then
		host="$@"
	elif [[ $@ =~ $ip3regex ]]; then
		host="192.$@"
	elif [[ $@ =~ $ip2regex ]]; then
		host="192.168.$@"
	elif [[ $@ =~ $ip1regex ]]; then
		host="192.168.1.$@"
	fi
	ping $host
}