shell scripting pipline to a variable

Question

I have the following:

FILENAME=$1
cat $FILENAME | while read LINE
do
       response="$LINE" | cut -c1-14
       request="$LINE" | cut -c15-31
       difference=($response - $request)/1000
       echo "$difference"
done

When I run this script it returns blank lines. What am I doing wrong?

Answer 1

Might be simpler in awk:

awk '{print ($1 - $2)/1000}' "$1"

I'm assuming that the first 14 chars and the next 17 chars are the first two blank-separated fields.

Answer 2

You need to change it to:

response=`echo $LINE | cut -c1-14`
request=`echo $LINE | cut -c15-31`
difference=`expr $response - $request`
val=`expr $difference/1000`

Answer 3

You are basically doing everything wrong ;) This should be better:

FILENAME="$1"
cat "$FILENAME" | while read LINE
do
       response=$(echo "$LINE" | cut -c1-14) # or cut -c1-14 <<< "$line"
       request=$(echo "$LINE" | cut -c15-31)
       difference=$((($response - $request)/1000)
       echo "$difference"
done