The shell implements a two number addition

Write at the beginning, always write wrong, seemingly simple function, but must be careful; function definition:

Funciton functionname {...} There must be a space between functionname and {! I just did not add a space, has been an error.

Implement two number additions:

#! /usr/bin/kshfunction Add {    if (($# < 2  ));        then "the arg in ' t correct"    C7>else            sum=$ (($1+$2))        echo $sum    11 2

Or

#! /usr/bin/kshfunction Add {    if (($# < 2  ));        then "the arg in ' t correct"    C7>else            sum=$ (($1+$2))        echo $sum    fi}sum=$ (add 1) print $sumsum=$ (add 1 2) print $sum

The output of the two results is:

The arg in ' t correct
3

The shell implements a two number addition