bash脚本 - 如果语句不按预期行为

发布于 2025-02-03 20:44:00 字数 1413 浏览 4 评论 0原文

这是我第一次玩Bash脚本，但是我只是不明白为什么如果语句不行为。无论我输入哪个输入，作为输入，我总是会返回第一个回声，只有在我输入Yes或否以外的任何其他内容时才能执行。

我尝试删除括号，用双引号封闭，但我对此无法理解。

这是代码：

#!/bin/bash

read -p 'Would you like to take driving lessons: ' choice
read -p 'Type your age: ' age

if [ $choice != 'yes' ] || [ $choice != 'no' ] 
then 
  echo 'Your choice must be either yes or no'
fi

这是输出：

$ ./test.sh        
Would you like to take driving lessons: yes
Type your age: 46
Your choice must be either yes or no
                                                                                                                                                                                                                                                                                                                           
$ ./test.sh        
Would you like to take driving lessons: no
Type your age: 63
Your choice must be either yes or no
                                                                                                                                                                                                                                                                                                                           
$ ./test.sh
Would you like to take driving lessons: dgdgf
Type your age: 76
Your choice must be either yes or no

只有最后一个运行才能返回回声语句。

原文

This is my first time playing with bash scripting, but I just cannot understand why this if statement is not behaving. No matter what input I enter into the choice variable as input I always get returned the first echo which should only execute if I input anything other than yes or no.

I've tried removing brackets, enclosing in double quotes, but I just can't make sense of this.

Here is the code:

#!/bin/bash

read -p 'Would you like to take driving lessons: ' choice
read -p 'Type your age: ' age

if [ $choice != 'yes' ] || [ $choice != 'no' ] 
then 
  echo 'Your choice must be either yes or no'
fi

Here is the output:

$ ./test.sh        
Would you like to take driving lessons: yes
Type your age: 46
Your choice must be either yes or no
                                                                                                                                                                                                                                                                                                                           
$ ./test.sh        
Would you like to take driving lessons: no
Type your age: 63
Your choice must be either yes or no
                                                                                                                                                                                                                                                                                                                           
$ ./test.sh
Would you like to take driving lessons: dgdgf
Type your age: 76
Your choice must be either yes or no

Only the last run should return the echo statement.

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污味仙女 2025-02-10 20:44:00

你很近。当它不等于时，您需要＆amp;。
这起作用：

#!/bin/bash

read -p 'Would you like to take driving lessons: ' choice
read -p 'Type your age: ' age

if [ $choice != 'yes' ] && [ $choice != 'no' ];
then
  echo 'Your choice must be either yes or no'
fi

它给出以下输出：

~ bash test.sh
Would you like to take driving lessons: yes
Type your age: 432
~ bash test.sh
Would you like to take driving lessons: fdsa
Type your age: 32
Your choice must be either yes or no

You were very close. You need && when it's not equal to.
This works:

#!/bin/bash

read -p 'Would you like to take driving lessons: ' choice
read -p 'Type your age: ' age

if [ $choice != 'yes' ] && [ $choice != 'no' ];
then
  echo 'Your choice must be either yes or no'
fi

It gives the following output:

~ bash test.sh
Would you like to take driving lessons: yes
Type your age: 432
~ bash test.sh
Would you like to take driving lessons: fdsa
Type your age: 32
Your choice must be either yes or no

回复收藏 0 原文

镜花水月 2025-02-10 20:44:00

您应该这样写：

#!/bin/bash

read -p 'Would you like to take driving lessons: ' choice
read -p 'Type your age: ' age

if [ $choice != 'yes' ] && [ $choice != 'no' ]
then
  echo 'Your choice must be either yes or no'
fi

You should write it like this:

#!/bin/bash

read -p 'Would you like to take driving lessons: ' choice
read -p 'Type your age: ' age

if [ $choice != 'yes' ] && [ $choice != 'no' ]
then
  echo 'Your choice must be either yes or no'
fi

回复收藏 0 原文

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