Question

I hope someone can help…

I’ve parsed integers to a file separated by carriage returns like so:

…
427562786
6834257
978539857
9742
578375
…

I wish to put these into an array and sum the total. However, after some fervent Googling, I can only find a reasonable way to do this using a for loop, which I’m on pretty good authority is not the best way to read a file line by line.

I understand that somewhere in this script I would need to declare something like this:

IFS=’
‘
while read line
do
array creation magic here
done < /tmp/file

SUM=0
while read line
do
SUM= sum array elements magic here
done < /tmp/file

printf $SUM

Please can someone more knowledgeable than me let me know what I’m missing? Thanks. 🙂

Answer 1

If the array is only an intermediate step and not required beyond that point then this takes you straight to the final answer:

sum=0
while read N
do
    # sum=$((sum+N)) - the line below shows a more concise syntax
    ((sum += N))
    echo "Added $N to reach $sum"
done < /tmp/list_of_numbers

echo $sum