bash script + php

Hello,
I want to move some of my bash scripts to php ( add samba user, add new PC in dhcp and etc. ).With Google, I found some articles for bash and php, but there is only simple examples, nothing for variables.
Example:

#!/bin/bash
status=`/usr/local/etc/rc.d/isc-dhcpd status`
############
echo -n "Enter hostname: "
read host
echo -n "Enter MAC: "
read mac
echo -n "Enter IP: "
read ip
echo -n "Restart dhcp(y/n): "
read dhcp
echo "host $host { " >> dhcpd.conf
echo "hardware ethernet $mac;" >> dhcpd.conf
echo "fixed-address $ip;" >> dhcpd.conf
echo "}" >> dhcpd.conf
if [ $dhcp = y ];then
echo "/usr/local/etc/rc.d/isc-dhcpd restart"
echo "$status"
else
echo "Done"
fi 

So I want to have a php field for $host, field for $mac and field for $ip.
Is there some articles or examples for this?
I have some php shells, but they are full with s*its.I wana to learn something.
Thanks

there is plenty of tutorials on the web. google php cli