How to get the modified value of variable outside the while loop reading from a file

babusek · #1 (**permalink**) 07-20-2009

Hi Friends ,
Sorry if this is a repeated question ,

Quote:

count=0
i=0
while read line
do
i=`expr $i + 1`
count= `expr $count + $i`
done < input.txt

echo " i Value =$i "
echo " Count Value = $count"

The input file contains 5 lines , so the the values of the variables i and count should b
i=5;
count=15

but the variables are not updating , the value of variables showing i=0 and count =0 only.

can any1 help me please.

palsevlohit_123 · #2 (**permalink**) 07-20-2009

Updated code below..

Code:

count=0
i=0
while read line
do
i=`expr "$i" + 1`
count=`expr "$count" + "$i"`
done < input.txt
echo " i Value =$i "
echo " Count Value = $count"

Output

Code:

 i Value =5
 Count Value = 15

babusek · #3 (**permalink**) 07-20-2009

Hi Palse,
Thanks For u r reply , i tried the same but the variables are not updated.
i value = 0
count value = 0

and iam using the bash shell

kshji · #4 (**permalink**) 07-20-2009

count= `expr $count + $i`
=>
count=`expr $count + $i`

Setting variable must the whole set to be in 1st argument.

Which shell you are using ?
If you have not old bsh, then you can write without using external expr.
Always add the correct shell to the 1st line in script, no need to take care of your interactive "keyboard" shell and for us it's easier to give solution.

Code:

#!/bin/ksh
count=0
i=0
while read line
do
     (( i=i+1 ))    # or  (( i+=1 ))
     (( count = count + i ))
done < input.txt

echo " i Value =$i "
echo " Count Value = $count"

kshji · #5 (**permalink**) 07-20-2009

Did you try this ?

Code:

#!/bin/bash
count=0
i=0
while read line
do
     (( i=i+1 ))    # or  (( i+=1 ))
     (( count = count + i ))
done < input.txt

echo " i Value =$i "
echo " Count Value = $count"
echo "my input file:"
cat input.txt

palsevlohit_123 · #6 (**permalink**) 07-20-2009

Code:

> cat temp.bash
count=0
i=0
while read line
do
i=`expr "$i" + 1`
count=`expr "$count" + "$i"`
done < input.txt
echo " i Value =$i "
echo " Count Value = $count"

 
> bash temp.bash
 i Value =5
 Count Value = 15

Sorry, i able to execute the same code in bash shell too.
Note : Did you given the variables with in double quote, Pls check

babusek · #7 (**permalink**) 07-20-2009

hii Palse,
sorry the variable values are not updating , let me post the code which i have written ( as u said)

Code:

#!/bin/bash
count=0
 i=0

 while read line
 do
   i=`expr "$i" + 1`
   count=`expr "$count" + "$i"`
   done < input.txt
echo " i value = $i";
echo " count value = $count";

and output is :
-bash-3.00$ sh readLine.sh
i value = 0
count value = 0

What do u say ?

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