[问题]求助，如下错误提示是什么意思？

[newlinux]

错误提示：
sh06-2.sh: 2: Program:: not found

[: 15: ==: unexpected operator
[: 15: ==: unexpected operator
[: 21: missing ]
[: 21: ==: unexpected operator


源程序如下：
#!/bin/bash
Program:
# This program will show the user's choice
# History:
# 2008/1/22 liukai First release
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin
export PATH

#Program body
read -p "please input (Y/N): " yn

if [ "$yn" == "Y" ] || [ "$yn" == "y" ]; then
echo "OK,continue"
exit 0
fi

if [ "$yn" == "N"] || [ "$yn" == "n" ]; then

echo "OK,continue"
exit 0
fi

echo "I don't know what is your choise" && exit 0

[patrickhe]

#!/bin/bash
# This program will show the user's choice
# History:
# 2008/1/22 liukai First release

#Program body
read -p "please input (Y/N): " yn

if [ "$yn" == "Y" -o "$yn" == "y" ]; then
echo "Yes"
exit 0
fi

if [ "$yn" == "N" -o "$yn" == "n" ]; then
echo "No"
exit 0
fi

或者

#!/bin/bash
# This program will show the user's choice
# History:
# 2008/1/22 liukai First release

#Program body
read -p "please input (Y/N): " yn

if [[ "$yn" == "Y" || "$yn" == "y" ]]; then
echo "Yes"
exit 0
fi

if [[ "$yn" == "N" || "$yn" == "n" ]]; then
echo "No"
exit 0
fi

[newlinux]

感谢 二楼回复！
我把你的两个脚本在我机子上运行，还是有如下错误,不知是那儿出了错！


+ read -p please input (Y/N): yn
please input (Y/N): y
+ [ y == Y -o y == y ]
[: 1: ==: unexpected operator
+ [ y == N -o y == n ]
[: 1: ==: unexpected operator

[eexpress]

"$yn"
改${yn}
没看你内容。慢慢man

[laborer]

感谢 二楼回复！
我把你的两个脚本在我机子上运行，还是有如下错误,不知是那儿出了错！


+ read -p please input (Y/N): yn
please input (Y/N): y
+ [ y == Y -o y == y ]
[: 1: ==: unexpected operator
+ [ y == N -o y == n ]
[: 1: ==: unexpected operator

你机器可能用的是dash而不是bash

[newlinux]

我装的是ubuntu7.10,刚接触shell，还望指点

[patrickhe]

执行
echo $SHELL
看一下自己用的到底是那个 shell。
我用的是 bash。

[newlinux]

我执行的结果是这个，我用的也是bash呀
echo $SHELL
/bin/bash