Multiplying numbers from each line in file is giving minus value

Question

#!/bin/bash

sed  's/[^0-9 ]*//g'  $1 | tr " " "\n" > outfile.txt

sed '/^\s*$/d' outfile.txt > outfile1.txt


if [ $2 == "-s" ] || [ $2 == "-si" ] || [ $2 == "-is" ]
then
sum=0;
while read num;
do ((sum += num));
done < outfile1.txt;
echo "SUMA= $sum"
fi

if [ $2 == "-i" ] || [ $2 == "-si" ] || [ $2 == "-is" ]
then
ilo=1;
while read num1;
do((ilo = num1 * ilo));
echo $num1
done < outfile1.txt;
echo "ILOCZYN= $ilo"
fi

this is my script and this is 1st argument file

1 2 3 4 5 4 3 2 3 4 5 4 3 
2 2 2 2 22 3 34 4 4 5 5 5 d 
3 43 54 5 3

this is what im getting from the script when i want to get an multiply of all the numbers and sum of them

s17545@msh:~$ ./skrypt12.sh logfile.txt -si
SUMA= 241
1
.
. all of the numbers in outfile1.txt 
.
3
ILOCZYN= -2888071394797551616

any ideas what i am doing wrong?

Possibly related: What is the rationale for the bash shell not warning you of arithmetic overflow etc.? — steeldriver, Jun 01 '18 at 23:09
So is there any walkabout or i am just fine to accept my destiny of limits :D? — Beforeu, Jun 01 '18 at 23:28
In theory, you could write an arbitrary precision arithmetic package for bash, but unless you take particular fun out of such a task, it is much easier to use instead one of those many programming languages which already come with such a feature. — user1934428, Jun 04 '18 at 05:14

score 2 · Accepted Answer · answered Jun 01 '18 at 23:43

2

As the page linked by @steeldriver explains, arithmetic overflow is a fact of life in Bash. You could instead:

use a language which supports arbitrary-size numbers out of the box such as (I believe) Haskell, Lisp or Scheme,
use a language which will throw an exception at arithmetic overflow, such as Java or Rust,
check whether the product has decreased after each operation (since all your numbers are positive), or
rethink your approach so that you don't need to multiply all the numbers in one go (which of course isn't always possible).

answered Jun 01 '18 at 23:43

l0b0

51,350

There's also dc e.g. sed -z 's/[^0-9][^0-9]*/*/2g' "$1" | dc -f - -ep – steeldriver Jun 02 '18 at 00:21
Python does bignums, and is likely already installed on more systems than the languages you name. Java does not throw for integer (primitive) overflow; it wraps-around. (For FP it uses IEEE which doesn't overflow at all but has +-Infinity values. For BigInteger, it does throw ArithmeticException or OutOfMemory, but only for humongous values.) – dave_thompson_085 Jun 02 '18 at 10:56

Multiplying numbers from each line in file is giving minus value

1 Answers1