Linux shell 编程字符串比较语法 [英] Linux shell programming string compare syntax

问题描述

=和==在Linux shell编程中比较字符串有什么区别?

What is the difference between = and == to compare strings in Linux shell programming?

也许下面的代码可以工作:

Maybe the following code works:

if [ "$NAME" = "user" ]
then
    echo "your name is user"
fi

但我认为这不是正确的语法.它将用于通过 == 语句比较字符串.

But I think it's not a correct syntax. It would be used to compare string by == statement.

什么是正确的?

推荐答案

这些页面解释了 bash 中的各种比较运算符:

These pages explain the various comparison operators in bash:

• http://www.tech-recipes.com/rx/209/bournebash-shell-scripts-string-comparison/
• http://tldp.org/LDP/abs/html/comparison-ops.html
• http://www.faqs.org/docs/Linux-HOWTO/Bash-Prog-Intro-HOWTO.html#ss11.2

在第二个链接页面上，您会发现:

On the second linked page, you will find:

==

    is equal to

    if [ "$a" == "$b" ]

    This is a synonym for =.

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