red hat 下的shell scripts 问题！！

#!/bin/bash
# Program:
# Let user keyin their first and last name, and show their full name.
# History:
# 2007/03/19 zhang First release
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin
export PATH

read -p "Please input your first name: " firstname
read -p "Please input your last name: " lastname
echo -e "\nYour full name is: $firstname $lastname"

这是网上的范例脚本，我绝对是照着做的，可是执行sh z1.sh
结果就是不去用参数。
Please input your first name:firstname111
Please input your last name: " lastname222

nYour full name is:

nYour full name is:这里不取用参数firstname lastname

我还有个就是path 那段是起什么作用，export 是什么意思！！