division operation in shell script - Shell Programming and Scripting

ragha81 · #1 (**permalink**) 10-23-2006

Hi guys

I am trying to divide 2 variables that I got during the execution of script, but I unable to divide the variables. pls help. Hers is the code.

Code:

num_tasks=`sqlplus -s batch_user/batch_user@acsblest << EOF1 
set heading off
SET FEEDBACK OFF
SET PAGESIZE 0
SET LINESIZE 900
select cp_num_run_ from fusionhc_chk where cc_alias = 'eCustomerCMEObjMgr_enu';
EOF1`

echo $num_tasks

max_tasks=`sqlplus -s batch_user/batch_user@acsblest << EOF2 
set heading off
SET FEEDBACK OFF
SET PAGESIZE 0
SET LINESIZE 900
select cp_max_task from fusionhc_chk where cc_alias = 'eCustomerCMEObjMgr_enu';
EOF2`
echo $max_tasks
per_load=$num_tasks/$max_tasks
echo $per_load
if [ "$per_load" -gt "0.95" ]
then
echo "not good"
fi
exit

i did a set -x and I get this

Code:

3
20
3/20

plz help..

Manish Jha · #2 (**permalink**) 10-23-2006

per_load=$(($num_tasks/$max_tasks))

This would give you only integer out put. Not sure if direct decimal o/p is possible . You could use awk to get the desired decimal out.

--Manish

jim mcnamara · #3 (**permalink**) 10-23-2006

First off, SQL provide for division:

Code:

result=\
`sqlplus -s batch_user/batch_user@acsblest << EOF1 
set heading off
SET FEEDBACK OFF
SET PAGESIZE 0
SET LINESIZE 900
select cp_num_run_ / cp_max_task 
      from fusionhc_chk 
      where cc_alias = 'eCustomerCMEObjMgr_enu';
EOF1`
echo $result

Floating point division in scripts depends on the shell - a general solution :

Code:

result=`echo "$num_tasks / max_tasks " | bc -l`
echo $result

vgersh99 · #4 (**permalink**) 10-23-2006

you cannot do float math natively with most shells.

ragha.sh 3 4
ragha.sh 9 10
ragha.sh 35 36

ragha.sh:

Code:

#!/bin/ksh

typeset -i num_tasks="${1}"
typeset -i max_tasks="${2}"

typeset threshold='.95'

echo "num->[$num_tasks]"
echo "max->[$max_tasks]"

per_load=$(echo "scale=2; $num_tasks / $max_tasks" | bc)

echo "per_load->[$per_load]"

if [ "$(echo "if (${per_load} > ${threshold}) 1" | bc)" -eq 1 ]; then
   echo "not good"
fi

ragha81 · #5 (**permalink**) 10-23-2006

thank you guys.. i modified the code as follows and got the output, but still i am unable to compare the two numbers, VGERSH, i know you explained this part.. but I am sorry to tell that I am unable to understand theat part. my understanding of shell script is very poor.

I used sql to do the division. here is the code and set -x output.

Code:

num_tasks=`sqlplus -s batch_user/batch_user@$SIEBEL_DB_ORACLESID << EOF2 
set heading off
SET FEEDBACK OFF
SET PAGESIZE 0
SET LINESIZE 900
select cp_num_run_ / cp_max_task 
      from fusionhc_chk 
      where cc_alias = 'eCustomerCMEObjMgr_enu';
EOF2`
echo $num_tasks
set -x
if [ $num_tasks > 0.95 ]
then
echo "not good"
fi
exit

set -x output

Code:

.15
+ [ .15 ]
+ 1> 0.95
+ echo not good
not good
+ exit

vgersh99 · #6 (**permalink**) 10-23-2006

you cannot compare floats natively within most of the shells either.
use the 'if' construct from my previous post:

Code:

if [ "$(echo "if (${$num_tasks} > '.95') 1" | bc)" -eq 1 ]; then
   echo "not good"
fi

ragha81 · #7 (**permalink**) 10-23-2006

hi vgersh.

I used the if statement that you gave. i get the following error.

Code:

.15
+ bc
srvr_load_check.ksh[42]: "if (${$num_tasks} > '.95') 1": bad substitution
+ [  -eq 1 ]
+ exit

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