Using decimals in shell scripts

[boebox]

Does anyone know how to use decimal numbers in a shell script?

expr only accepts integers!

Thanks
Tony

 

[Krunek]

Hi, boebox!

You can use decimal numbers in a awk and perl scripts, as I know. Sorry, maybe you also know this.

You can post your programming problem.

KP.

 

[grega]

In what context are you using them? ... shell scripts don't really have any concept of data types, but you could use awk/nawk along with the printf function which handles this sort of thing easily.

Could you post an example of what you're trying to do?

Greg.

 

[boebox]

#!/bin/sh

var1=0
i=0

for ;;
do
var2=`mycommand | awk '{ print $4 }' => decimal number (6.7)
var1=$var2 + $var1
i=$i+1
done

var3=var2 / $i

 

[RobJordan]

I just ran into this problem myself
and was able to solve it using bc.
Below, look for the text scale=2.
That sets the results to 2 decimal postions.

Robert

#/usr/local/bin
# disk_space
# usage: disk_space [/path]
# works much like the command du
# but oputs in k,kb,mb and gb

################################################################################
# Variables
################################################################################
TMP_LIST=/tmp/TMP_LIST.disk_space.$$ # generic tmp file for data

################################################################################
# Functions
################################################################################
Disk_Usage ()
{
KB_TOTAL=`du -sk $DIR|awk '{print $1}'`
}

################################################################################
# Main
################################################################################

DIR=$1
Disk_Usage

echo "scale=2" >> $TMP_LIST.kb
echo "${KB_TOTAL}*1000" >> $TMP_LIST.kb
echo "quit" >> $TMP_LIST.kb
K_TOTAL=`bc $TMP_LIST.kb`

echo "scale=2" >> $TMP_LIST.mb
echo "${KB_TOTAL}/1000" >> $TMP_LIST.mb
echo "quit" >> $TMP_LIST.mb
MB_TOTAL=`bc $TMP_LIST.mb`

echo "scale=2" >> $TMP_LIST.gb
echo "${KB_TOTAL}/1000000" >> $TMP_LIST.gb
echo "quit" >> $TMP_LIST.gb
GB_TOTAL=`bc $TMP_LIST.gb`

echo
echo " K TOTAL: $K_TOTAL"
echo "KB TOTAL: $KB_TOTAL"
echo "MB TOTAL: $MB_TOTAL"
echo "GB TOTAL: $GB_TOTAL"
echo

################################################################################
# End
################################################################################

test run...
# ./disk_space /var

K TOTAL: 769390000
KB TOTAL: 769390
MB TOTAL: 769.39
GB TOTAL: .76

Robert G. Jordan

Robert@JORDAN2000.com
Unix Admin, United Airlines