how to get variable to re-evaluate itself?

Shell Programming and Scripting
1

Probably a simple one.
Basically I am retrieving a number from a file - setting a variable against it and then incrementing this by 1 and using this as an entry number in a log file for messages. I need the variable to re-evalute itself each time I call it so I get the latest number in the file - how do I do this? my script is basically as follows:

The number within test4.csv is updated every 2 seconds ... so the second time I echo $e I hope to see the latest number incremented by one

#!/usr/bin/ksh

d=`tail -1 test4.csv | cut -f1 -d" "`
e=$((d + 1))

echo e is $e
sleep 3
echo e is $e
sleep 3

2

I am not sure if this will help so much.

Why not put your code a while true loop ?

#!/usr/bin/ksh

while :
do
d=$(tail -1 test4.csv | cut -f1 -d" ")
e=$((d + 1))
echo e is $e
sleep 3
done