菜鸟求教高手条件判断语句if的问题，怎么也找不到错误

[lvkangpeng]

弄了一下午，查了几本书，应该没问题啊
脚本如下
#!/bin/bash
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 "Oh,interrupt"
exit 0
fi
echo "I don't know what is your choise"&& exit 0

执行结果是：
Please input (Y/N):y
./if_ex3: line 3: [y==Y]：找不到命令
./if_ex3: line 3: [y==y]：找不到命令
./if_ex3: line 7: [y==N]：找不到命令
./if_ex3: line 7: [y==n]：找不到命令
I don't know what is your choise

[JiangHui]

代码： 全选

#!/bin/bash
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 "Oh,interrupt"
exit 0
fi
echo "I don't know what is your choise"&& exit 0

[JiangHui]

注意空格

[JiangHui]

另外你这脚本本身就有问题，再好好看看

[lvkangpeng]

太感谢了，

实在不好意思，没仔细注意书上的空格

搞定了！谢谢

[lvkangpeng]

是照抄的《Ubuntu权威指南》（人民邮电出版社）第8章的例子
这段原来本身有问题
现在懂的太少了，记下来，等回头多看看书再研究
可能选书选错了
应该选《鸟哥的Linux私房菜_基础学习篇》
好像很多人推荐
省钱，买了

[JiangHui]

鸟哥里面有教shell吗？论坛有人发过pdf，搜下

[lvkangpeng]

程序还是不对
难道不能用
"$yn"=="Y"
这种方式
用-eq ？

[JiangHui]

你把2楼的重新复制上去看看

我只是说这么写太麻烦了

[hepha]

#!/bin/bash
read -p "Please input (Y/N):" yn
if [[ "$yn" == "Y" || "$yn" == "y" ]];then
echo "OK,continue"
exit 0
else
echo "I don't know what is your choise" && exit 0
fi

[trigger]

#!/bin/bash
read -p "keyin Y or N : " yn
[ $yn == "Y" ] && echo "hi man"
[ $yn == "N" ] && echo "hi guy"
[ $yn != "Y" ] && [ $yn != "N" ] && echo "who are you"

[xiooli]

[ 其实是一个命令，后边的东西是它的参数（] 也是参数），所以要空格分隔

[tusooa]

代码： 全选

tlcr: 0 庚寅年六月初五日 10:45:42  ~
>> type [
[ is a shell builtin
tlcr: 0 庚寅年六月初五日 10:52:50  ~
>>