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Shell Korn Shell 运算符

2021-08-31 09:16:50 更新

本教程列出了所有Korn Shell中的运算符。在这里,大部分的运算符都是我们熟知的C语言编程很相似。

运算符优先级递减的顺序如下列出:

算术和逻辑运算符:

运算符 描述
+ Unary plus
- Unary minus
!~ Logical negation; binary inversion (one's complement)
* Multiply
/ Divide
% Modulo
+ Add
- Subtract
<< Left shift
>> Right shift
== String comparison for equality
!= String comparison for non equality
=~ Pattern matching
& Bitwise "and"
^ Bitwise "exclusive or"
| Bitwise "inclusive or"
&& Logical "and"
|| Logical "or"
++ Increment
-- Decrement
= Assignment

文件测试操作:

有以下运算符测试可用在Unix文件中的相关联各种属性。

运算符 描述
-r file Checks if file is readable if yes then condition becomes true.
-w file Check if file is writable if yes then condition becomes true.
-x file Check if file is execute if yes then condition becomes true.
-f file Check if file is an ordinary file as opposed to a directory or special file if yes then condition becomes true.
-s file Check if file has size greater than 0 if yes then condition becomes true.
-d file Check if file is a directory if yes then condition becomes true.
-e file Check if file exists. Is true even if file is a directory but exists.