Korn Shell Programming by Example

integer

Official Description

Declares a variable as an integer.

Syntax

integer [variable[=value]]

Options

None

Oddities

integer is an alias for typeset -i.

Makes calculations faster. Shell has to convert strings to integers before performing a calculation.

Example

$ a=17
$ b=22
$
$ time for (( i=0; i<1000; i++ ))
> do
> (( c = $a + $b ))          # Do calculations using strings
> done

real    0m0.26s
user    0m0.26s
sys     0m0.00s
$
$ integer d e f              # Declare variables as integers
$
$ d=17
$ e=22
$
$  time for (( i=0; i<1000; i++ ))
> do
> (( f = e + d ))            # Do calculations using integers
> done

real    0m0.16s              # Much faster
user    0m0.16s
sys     0m0.00s
$