How can I quickly sum all numbers in a file?

Question

I have a file which contains several thousand numbers, each on it's own line:

34
42
11
6
2
99
...

I'm looking to write a script which will print the sum of all numbers in the file. I've got a solution, but it's not very efficient. (It takes several minutes to run.) I'm looking for a more efficient solution. Any suggestions?

Answer 1

I don't know if you can get a lot better than this, considering you need to read through the whole file.

$sum = 0;
while(<>){
   $sum += $_;
}
print $sum;

Answer 2

You can use awk:

awk '{ sum += $1 } END { print sum }' file

Answer 3

For a Perl one-liner, it's basically the same thing as the awk solution in Ayman Hourieh's answer:

 % perl -nle '$sum += $_ } END { print $sum'

If you're curious what Perl one-liners do, you can deparse them:

 %  perl -MO=Deparse -nle '$sum += $_ } END { print $sum'

The result is a more verbose version of the program, in a form that no one would ever write on their own:

BEGIN { $/ = "\n"; $\ = "\n"; }
LINE: while (defined($_ = <ARGV>)) {
    chomp $_;
    $sum += $_;
}
sub END {
    print $sum;
}
-e syntax OK

Just for giggles, I tried this with a file containing 1,000,000 numbers (in the range 0 - 9,999). On my Mac Pro, it returns virtually instantaneously. That's too bad, because I was hoping using mmap would be really fast, but it's just the same time:

use 5.010;
use File::Map qw(map_file);

map_file my $map, $ARGV[0];

$sum += $1 while $map =~ m/(\d+)/g;

say $sum;

Answer 4

Pash (aka PowerShell for Linux :)):

(gc "input.txt" | measure -sum).Sum > "output.txt"

Answer 5

echo $(for i in $(cat numbers.txt); do echo -n "$i+"; done ; echo 0) | bc

I am curious to see how it performs (it might reach memory limits).

Answer 6

Just to be ridiculous:

cat f | tr "\n" "+" | perl -pne chop | R --vanilla --slave

Answer 7

This is straight Bash:

sum=0
while read -r line
do
    (( sum += line ))
done < file
echo $sum

Answer 8

I have not tested this but it should work:

cat f | tr "\n" "+" | sed 's/+$/\n/' | bc

You might have to add "\n" to the string before bc (like via echo) if bc doesn't treat EOF and EOL...

Answer 9

sed ':a;N;s/\n/+/;ta' file|bc

Answer 10

Here's another one-liner

( echo 0 ; sed 's/$/ +/' foo ; echo p ) | dc

This assumes the numbers are integers. If you need decimals, try

( echo 0 2k ; sed 's/$/ +/' foo ; echo p ) | dc

Adjust 2 to the number of decimals needed.