Hi,

I face difficulty where the number which I grep before I would like to use it as number to grep again in another file.

For example in file 1, I extract the second field and assign to variable "char" in a while loop. And then, I grep again this char to get i and j.

char=`echo "${LINE}"| awk '{print $2}'`

echo $char

i=`grep -n "^$char" b.txt|awk '{print $2}'`
j=`grep -n "^$char" b.txt|awk '{print $3}'`

I tried to use $i and $j for operation such that q=$i+$j; however, it gives me error.

Besides, I tried to grep again this "char" in another file using grep -n char$ file2 but it doesnt work. (In a typical example : grep -n element$ filename should give us the exact line of element)

Please advise. Thanks.

-Jason

Do you want to add them numerically?

or literally?

do you have sample files?

Are you sure i and j are numbers?

Hi Zelp,

These are numbers. And basically in a while loop, I do not declare awk. Most of the time, I only do echo which in the end I could not use printf.

Sample code:-

#!/bin/bash

cat a.txt|while read LINE
do

char=`echo "${LINE}"| awk '{print $2}'`

#echo $char
i=`grep -n "^$char" b.txt|awk '{print $2}'`
j=`grep -n "^$char" b.txt|awk '{print $3}'`
k=`grep -n $char$ c.txt|awk '{print $1}'`

echo $i
echo $j
echo $k


q=`echo (($j)/($i+$j))|bc `

echo $q

#awk '{
#q=$j/($i+$j)}

#END{

#printf("q is %d", $q);
#}'

done

I have error in echo where it doesnt allow me to perform computation. I am thinking to use AWK whihc is put easier but I could not because it invovles multiple files to read and compare.

Please advise what is the best solution for this. Thanks!


-Jason

Did you not see my

?

Yeap porter,
But my computation is complex which is

$j/$i+$j.

Please advise. Thanks.

-Jason