bash 在 shell 脚本中使用 if elif fi
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Using if elif fi in shell scripts
提问by Zenet
I'm not sure how to do an ifwith multiple tests in shell. I'm having trouble writing this script:
我不确定如何if在 shell 中进行多个测试。我在编写此脚本时遇到问题：
echo "You have provided the following arguments $arg1 $arg2 $arg3"
if [ "$arg1" = "$arg2" && "$arg1" != "$arg3" ]
then
echo "Two of the provided args are equal."
exit 3
elif [ $arg1 = $arg2 && $arg1 = $arg3 ]
then
echo "All of the specified args are equal"
exit 0
else
echo "All of the specified args are different"
exit 4
fi
The problem is I get this error every time:
问题是我每次都会收到此错误：
./compare.sh: [: missing `]' command not found
./compare.sh: [: 未找到缺少的 `]' 命令
采纳答案by Josh Lee
shis interpreting the &&as a shell operator. Change it to -a, that's ['s conjunction operator:
sh将 解释&&为 shell 运算符。将其更改为-a，这是[的连接运算符：
[ "$arg1" = "$arg2" -a "$arg1" != "$arg3" ]
Also, you should always quote the variables, because [gets confused when you leave off arguments.
此外，你应该总是引用变量，因为[当你离开参数时会感到困惑。
回答by Splitlocked
Josh Lee's answer works, but you can use the "&&" operator for better readability like this:
Josh Lee 的答案有效，但您可以使用“&&”运算符来提高可读性，如下所示：
echo "You have provided the following arguments $arg1 $arg2 $arg3"
if [ "$arg1" = "$arg2" ] && [ "$arg1" != "$arg3" ]
then
echo "Two of the provided args are equal."
exit 3
elif [ $arg1 = $arg2 ] && [?$arg1 = $arg3 ]
then
echo "All of the specified args are equal"
exit 0
else
echo "All of the specified args are different"
exit 4
fi
回答by Henryk Konsek
Use double brackets...
使用双括号...
if [[ expression ]]
if [[ expression ]]
回答by Gaurav Kolarkar_InfoCepts
I have a sample from your code. Try this:
我有一个来自您的代码的示例。尝试这个：
echo "*Select Option:*"
echo "1 - script1"
echo "2 - script2"
echo "3 - script3 "
read option
echo "You have selected" $option"."
if [ $option="1" ]
then
echo "1"
elif [ $option="2" ]
then
echo "2"
exit 0
elif [ $option="3" ]
then
echo "3"
exit 0
else
echo "Please try again from given options only."
fi
This should work. :)
这应该有效。:)
回答by Ethan Post
Change "[" to "[[" and "]" to "]]".
将“[”更改为“[[”并将“]”更改为“]]”。
回答by Ranjithkumar T
This is working for me,
这对我有用，
# cat checking.sh
#!/bin/bash
echo "You have provided the following arguments $arg1 $arg2 $arg3"
if [ "$arg1" = "$arg2" ] && [ "$arg1" != "$arg3" ]
then
echo "Two of the provided args are equal."
exit 3
elif [ $arg1 == $arg2 ] && [ $arg1 = $arg3 ]
then
echo "All of the specified args are equal"
exit 0
else
echo "All of the specified args are different"
exit 4
fi
# ./checking.sh
You have provided the following arguments
All of the specified args are equal
You can add "set -x" in script to troubleshoot the errors,
您可以在脚本中添加“set -x”来解决错误，
Thanks.
谢谢。
