Shell Programming and Scripting

Within a ksh script on HP-UX I trying to calculate a percentage of a number (number/100 x percentage) using the below method and expr.

TARPERC=`expr 16 / 100 \* 5`
TARSUM=`expr 16 + $TARPERC`
ZIPSUM=`expr $TARSUM \* 2`

If the input is 16

outputs are:
TARPERC: 0
TARSUM: 16
ZIPSUM: 32

The output should be 0.8 or thereabouts.

expr is dealing with the first calculation but is outputting the result as 0. Is there any way of doing this using expr or can you recommend a command and syntax that can handle floating points that can use in my script ?

hope this makes sense

Thanks

What about awk?

Code:

echo |awk '{print 16 / 100 * 5}'

Regards.

Thanks, that works. Additional question: How would I substitute a variable for the value of 16 ?

TARPERC=`awk '{print ${SUM} / 100 * 5}'`

Doesn't seem to work. Awk moans about the $SUM variable

Code:

export KK=16
echo |awk '{print a / 100 * 5}' a=$KK

With awk :

Code:

$ sum=123
$ awk "END {print $sum / 100 * 5}" </dev/null
6.15
$ awk 'END {print '$sum' / 100 * 5}' </dev/null
6.15
$ awk 'END {print val / 100 * 5}' val=$sum </dev/null
6.15
$

Another way :

Code:

$ echo "scale=2; $sum / 100 * 5" | bc
6.15
$

Jean-Pierre.

Thank you all, managed to get to work using:

TARPERC=`echo |awk '{print a / 100 * 5}' a=$SUM`

No need to use awk or expr. ksh is capable of doing want you want.

Code:

#!/bin/ksh

TARPERC=$((16.00/100.00*5.00))
TARSUM=$((16+$TARPERC))
ZIPSUM=$(($TARSUM*2))

print $TARPERC
print $TARSUM
print $ZIPSUM

which ouputs

Code:

0.8
16.8
33.6