（七）语法：跟用户交互

#!/bin/bash

# reply.sh

# REPLY是'read'命令结果保存的默认变量.

echo

echo -n "What is your favorite vegetable? "

read

echo "Your favorite vegetable is $REPLY."

# 当且仅当在没有变量提供给"read"命令时,

#+ REPLY才保存最后一个"read"命令读入的值.

echo

echo -n "What is your favorite fruit? "

read fruit

echo "Your favorite fruit is $fruit."

echo "but..."

echo "Value of \$REPLY is still $REPLY."

# $REPLY还是保存着上一个read命令的值,

#+ 因为变量$fruit被传入到了这个新的"read"命令中.

echo

exit 0