Using the let command for arithmetic
We can use the bash built-in command let for performing arithmetic operations.
To get more information about let, type the following:
$ help letThis should produce the following output of this command:
Let's start using the let command:
$ value=6$ let value=value+1$ echo $value7$ let "value=value+4"$ echo $value11$ let "value+=1"#above expression evaluates as value=value+1$ echo $value12
A summary of operators available with the let command follows:
- Operation:
Operator - Unary minus:
- - Unary plus:
+ - Logical NOT:
! - Bitwise NOT (negation):
~ - Multiply:
* - Divide:
/ - Remainder:
% - Subtract:
- - Add:
+
Prior to Bash 2.x, the following operators were not available:
- Bitwise left shift:
<< - Bitwise right shift:
>> - Equal to and not equal to:
==,!= - Comparison operators:
<=, >=, <, > - Bitwise
AND:& - Bitwise
OR:| - Bitwise exclusive
OR:^ - Logical
AND:&& - Logical
OR:|| - Assignment and shortcut assignment:
= *=/= %= -= += >>= <<= &= |= ^=
