If you're ever thought of summing up more than two numbers in shell script, perhaps this basic post will be a good start for your Unix scripting experiments.
Basic construction for summing up in shell scripts
In my Basic arithmetic operations in Unix shell post last year, I've shown you how to sum up two numbers:
SUM=$(($NUMBER1 + $NUMBER2)
using the same approach, it's possible to calculate sums of as many numbers as you like, if you use one of the loops available in your shell.
Before we get started, let's create a simple file with numbers we'll work with:
ubuntu$ for i in 1 2 3 4 5 6 7 8 9; do echo $i >> /tmp/nums; done; ubuntu$ cat /tmp/nums 1 2 3 4 5 6 7 8 9
Using a while loop to sum numbers up in Unix
Here's an example of how you can use a while loop in Unix shell for summing numbers up. Save it as a /tmp/sum.sh script, and don't forget to do chmod a+x /tmp/sum.sh so that you can run it!
#!/bin/sh
#
SUM=0
#
while read NUM
do
echo "SUM: $SUM";
SUM=$(($SUM + $NUM));
echo "+ $NUM: $SUM";
done < /tmp/nums
Here's how the output will look when you run it:
ubuntu$ /tmp/sum.sh SUM: 0 + 1: 1 SUM: 1 + 2: 3 SUM: 3 + 3: 6 SUM: 6 + 4: 10 SUM: 10 + 5: 15 SUM: 15 + 6: 21 SUM: 21 + 7: 28 SUM: 28 + 8: 36 SUM: 36 + 9: 45
Of course, your data will most probably will be in a less readable form, so you'll have to do a bit of parsing before you get to sum the numbers up, but the loop will be organized in the same way.
That's it for today, enjoy and feel free to ask questions!
See also:
Hello,
Can you please provide the following codes:
1. I divide 20 /6 . The answer id now 3. It sould be 3.33
2. How to do 10.222 + 1.1 = 11.322
Thanks in advance. 🙂
Hello Ankan,
you need to use "scale" option from bc:
echo 'scale=25;57/43' | bc
Scale controls the number of decimal points. Not sure if scale is an option, command or what not… but that's your answer.
Regards,
Pete
You can make your code tighter in ksh and bash:
SUM+=$NUM
instead of
SUM=$(($SUM + $NUM))
Also, you can use an awk one-liner instead of a while loop:
for i in 1 2 3 4 5; do echo $i; done | awk '{s+=$1} END {print s}'
or
cat | awk '{s+=$1} END {print s}'
1
2
3
4
5
^d
15 (result)
Hi Pete
Thanks for your response, But the problem is that in below example
echo 'scale=25;57/43′ | bc
Values 57 and 43 are in variables in my script
i.e.
a=57
b=43
echo 'scale=25;$a/$b′ | bc
Above does not work 🙁
Plz help
Rgds
Neeraj Batra
Neeraj Batra, you would need double quotes instead of single quotes to allow the shell to interpret the variables.
Hello
I'm trying to sum a field in a | delimited file but not receiving the correct value. Not sure how I'm getting e+06. Please help
cat file.TXT |awk 'FS = "|" { sum += $12 } END { print sum }'|xargs -n1|while read sum ;do aa='$'$sum ;done
echo $aa
7.60411e+06
Thank you
i have 3 values in one varirable and 5 values in another variable and i need to find out differnce between these values one by one in shell script