UNIX for Dummies Questions & Answers

use expr instead
if u have variables a and b
c=` expr $a+$b `

Code:

>echo 1.3 3.4 | awk '{print $1 + $2}'
4.7
>echo 1.3 3.4 | awk '{print $1 / $2}'
0.382353
>echo 1.3 3.4 | awk '{print $1 * $2}'
4.42
>echo 1.3 3.4 | awk '{print $1 - $2}'
-2.1

The awk method, at least, should work perfectly well.

#!/bin/ksh
a=1.3
b=3.4
c=`echo $a + $b | bc`
echo "The value is $c"
exit 0

Try this....

Code:

[rick@kangaroo ~]$ a=1.3
[rick@kangaroo ~]$ b=5.1
[rick@kangaroo ~]$ c=$(echo $a + $b | bc)
[rick@kangaroo ~]$ echo $c
6.4
[rick@kangaroo ~]$

a=2
b=3
c='echo $a+$b | bc'
echo $c


# two variables with operator + in between are echoed as a string
and passed on to bc to evaluate, which is stored in variable c.

a=2
b=9
c='echo $a+$b | bc'
echo $c


this should work

The best way to use maths function is by "bc" command. It takes care of integer and float both.
Usage: echo the maths expression and pipe it to bc.
add:
===
$ echo "2+2" | bc
$ 4
$ echo "2.5+4.8" | bc
$ 7.3

multiply:
======
$ echo "2.5*4.6" | bc
$ 11.5

Getting Powers:
============
$ echo "2 ^ 6" | bc
$ 64

You can define the precision scale i.e. the number of digits you want after decimal by using scale command.

For Example, for division
$ echo "scale=9; 22 / 7" | bc
3.142857142

or for square root:
$ echo "scale=5;sqrt ( 2 )" | bc
$ 1.41421


There are many more function in bc.....
s(x): Sine
c(x): Cosine
e(x): Exponential
l(x): Log
a(x): arctangent
..
..
..

Hope this helps!!!