Shell 脚本语法错误 if [[ $Char == [AZ] -o $Char == [az] ]]

发布于 2025-01-16 04:13:10 字数 919 浏览 0 评论 0原文

在下面提到的代码中，该行 if [[ $Char == [AZ] -o $Char == [az] ]] 显示以下错误

symbol.sh: line 2: 条件表达式中的语法错误

symbol.sh: line 2: `-o' 附近的语法错误

read -p "Enter the Character " Char
if [[ $Char == [A-Z] -o $Char == [a-z] ]] 
then 
    echo "The Character entered is an ALPHABET"
elif [[ $Char == [0-9] ]]
then
    echo "The Character entered is a NUMBER"
else
    echo "The Character entered is a Special Symbol"    
fi

我尝试以其他方式执行此操作，效果很好。

read -p "Enter the Character " Char
if [[ $Char == [a-z] ]] 
then 
    echo "The Character entered is an ALPHABET"
elif [[ $Char == [A-Z] ]] 
then 
    echo "The Character entered is an ALPHABET"
elif [[ $Char == [0-9] ]]
then
    echo "The Character entered is a NUMBER"
else
    echo "The Character entered is a Special Symbol"    
fi

我只是想知道这行代码有什么问题 if [[ $Char == [AZ] -o $Char == [az] ]]

原文

In the below mentioned code the line
if [[ $Char == [A-Z] -o $Char == [a-z] ]]
shows the following error

symbol.sh: line 2: syntax error in conditional expression

symbol.sh: line 2: syntax error near `-o'

read -p "Enter the Character " Char
if [[ $Char == [A-Z] -o $Char == [a-z] ]] 
then 
    echo "The Character entered is an ALPHABET"
elif [[ $Char == [0-9] ]]
then
    echo "The Character entered is a NUMBER"
else
    echo "The Character entered is a Special Symbol"    
fi

I tried doing it the other way and it works fine.

read -p "Enter the Character " Char
if [[ $Char == [a-z] ]] 
then 
    echo "The Character entered is an ALPHABET"
elif [[ $Char == [A-Z] ]] 
then 
    echo "The Character entered is an ALPHABET"
elif [[ $Char == [0-9] ]]
then
    echo "The Character entered is a NUMBER"
else
    echo "The Character entered is a Special Symbol"    
fi

I just want to know what is wrong with this line of code
if [[ $Char == [A-Z] -o $Char == [a-z] ]]

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挽清梦 2025-01-23 04:13:10

您混淆了各种比较运算符的语法。 test（或[）命令确实使用-o语法作为“or”运算符，但是 [[条件构造具有不同的语法；在那里，-o 检查是否启用了给定的 shell 选项。要使用 [[ 获得“或”，请在测试之间使用 || 语法：

if [[ $Char == [A-Z] ]] || [[ $Char == [a-z] ]] 
then 
# ...

您也可以使用针对您的语言环境的字符类进行测试的 bash 语法：

#!/bin/bash
read -p "Enter the Character " Char
if [[ $Char == [[:alpha:]] ]]
then
    echo "The Character entered is an ALPHABET"
elif [[ $Char == [[:digit:]] ]]
then
    echo "The Character entered is a NUMBER"
else
    echo "The Character entered is a Special Symbol"
fi

You've mixed up the syntax for the various comparison operators. The test (or [) command does use the -o syntax to be an "or" operator, but the [[ conditional construct has a different syntax; there, -o checks to see if the given shell option is enabled. To get an "or" with [[, use the || syntax between tests:

if [[ $Char == [A-Z] ]] || [[ $Char == [a-z] ]] 
then 
# ...

You could alternatively use the bash syntax that tests against your locale's character classes:

#!/bin/bash
read -p "Enter the Character " Char
if [[ $Char == [[:alpha:]] ]]
then
    echo "The Character entered is an ALPHABET"
elif [[ $Char == [[:digit:]] ]]
then
    echo "The Character entered is a NUMBER"
else
    echo "The Character entered is a Special Symbol"
fi

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