Linux 命令（231）—— let 命令（builtin）

let arg [arg ...]

id++, id--      	variable post-increment, post-decrement
++id, --id      	variable pre-increment, pre-decrement
-, +            	unary minus, plus
!, ~            	logical and bitwise negation
**              	exponentiation
*, /, %         	multiplication, division, remainder
+, -            	addition, subtraction
<<, >>          	left and right bitwise shifts
<=, >=, <, >    	comparison
==, !=          	equality, inequality
&               	bitwise AND
^               	bitwise XOR
|               	bitwise OR
&&              	logical AND
||              	logical OR
expr ? expr : expr	conditional operator
=, *=, /=, %=, +=, -=, <<=, >>=, &=, ^=, |=      assignment

let a=1+1

echo $a
2

let a++

echo $a
3

let a=2-1

echo $a
1

let a--

echo $a
0

let a=2
let a=a**10

echo $a
1024

let a=1||0

echo $a
1