Bash Arithmetic
Syntax#
-
$(( EXPRESSION )) - Evaluates expression and returns its result.
-
expr EXPRESSION - Prints result of EXPRESSION to stdout.
Parameters#
| Parameter | Details |
|---|---|
| EXPRESSION | Expression to evaluate |
| ## Remarks# | |
| A space (” ”) is required between each term (or sign) of the expression. “1+2” won’t work, but “1 + 2” will work. | |
| ## Arithmetic command |
Simple arithmetic with (( ))
#!/bin/bash
echo $(( 1 + 2 ))Output: 3
# Using variables
#!/bin/bash
var1=4
var2=5
((output=$var1 * $var2))
printf "%d\n" "$output"Output: 20
Simple arithmetic with expr
#!/bin/bash
expr 1 + 2Output: 3