UNIX for Dummies Questions & Answers

I am new to unix and the following problem is bugging me.

var1="hello1"
var2="hello2"
var3="hello3"
counter=1
while [ $counter -le 3]
do

echo $var$counter

done

the idea here is to display the value of "var" based on the counter.
I am using the korn shell. I used array here but the problem is that I am executing the script from another script and so the prompt comes as "-A bad option"
Can the above problem be done in another way i.e without using arrays.
Can eval be useful here? please help.
code snippet for this would be very helpful

TIA

eval is useful here and this sample shows how it works:

Code:

#!/bin/sh

var1="hello1"
var2="hello2"
var3="hello3"
counter=1

while [ $counter -le 3 ]
do
  eval "eval_var=\$var${counter}"
  echo ${eval_var}
  let counter=counter+1
done

The backslash before the "$" sign in the eval command is to prevent the shell to expand the variable.

Regards

If you are using Kornshell 93 (ksh93) instread of ksh88 or pdksh, the following works

Code:

#!/bin/ksh93

var1="hello1"
var2="hello2"
var3="hello3"

for (( counter=1; counter <= 3; counter++ ))
do
   nameref myvar="var"${counter}
   print $myvar
done

try this method, This way you can forget about hard coding your numeric of "3" so you know where to stop on your loop.

This adds the ability to add as many dymanic vars as you want.

Enjoy!

# You can set the array in two ways
# Method 1
# hellos="hello1 hello2 hello3"
# set -A myvar $hellos

#Method two
# myvar[0]="hello1"
# myvar[1]="hello2"
# myvar[2]="hello3"

# if your useing only one array then use what you
# feel is best for you.
# Method two offerres the option of adding more arrays
# that have a direct association to each other
# for example:

myvar[0]="hello1" ; othervar[0]="Bob"
myvar[1]="hello2" ; othervar[1]="Joe"
myvar[2]="hello3" ; othervar[2]="Mary"


count=0

# by using the ${#myvar[*]} you can add as many
# "myvars" and "othervars" as you want with out
# the need to rememdber the modify the max counter
# thus knowing where to end your loop.

while [ $count -lt ${#myvar[*]} ]
do
echo "${myvar[${count}]} - ${othervar[${count}]}"
let count=$count+1
done

thanks for the reply....igot one more solution .. to use eval

var=var$counter
eval var =\$$var

it works fine