Passing command line arguments to shell scripts allow you to re-use a lot of scripts. In shell scripts the command you execute is always the reserved variable of $0 each additional command is seperated by spaces. So for example if you typed:
./max_it special cheese now
$0 = max_it
$1 = special
$2 = cheese
$3 = now
$n is the number of arguments passed on the command line starting with 0
When providing command line arguments it is best to providing some sanity checking:
if [ $n -nq 1 ]
then
echo "Usage : $0 IP_address
exit
fi