本教程列出了所有C Shell的运算符。在这里,大部分的运算符都是跟C语言编程很相似。
运算符优先级递减的顺序如下:
算术和逻辑运算符:
运算符 | 描述 |
---|---|
( ) | Change precedence |
~ | 1's complement |
! | Logical negation |
* | 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 |
*= | Multiply left side by right side and update left side |
/= | Divide left side by right side and update left side |
+= | Add left side to right side and update left side |
-= | Subtract left side from right side and update left side |
^= | "Exclusive or" left side to right side and update left side |
%= | Divide left by right side and update left side with remainder |
文件测试操作:
有以下操作测试与Unix文件相关联的各种属性。
操作符 | 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. |
-z 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. |
-o file | Check if user owns the file. It returns true if user is the owner of the file. |