[linux] How can I quickly sum all numbers in a file?

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?

In shell using awk, I have used below script to do so:

    #!/bin/bash


total=0;

for i in $( awk '{ print $1; }' <myfile> )
do
 total=$(echo $total+$i | bc )
 ((count++))
done
echo "scale=2; $total " | bc

More succinct:

# Ruby
ruby -e 'puts open("random_numbers").map(&:to_i).reduce(:+)'

# Python
python -c 'print(sum(int(l) for l in open("random_numbers")))'

You can use awk:

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

Bash variant

raw=$(cat file)
echo $(( ${raw//$'\n'/+} ))

$ wc -l file
10000 file

$ time ./test
323390

real    0m3,096s
user    0m3,095s
sys     0m0,000s

Just for fun, lets do it with PDL, Perl's array math engine!

perl -MPDL -E 'say rcols(shift)->sum' datafile

rcols reads columns into a matrix (1D in this case) and sum (surprise) sums all the element of the matrix.

It is not easier to replace all new lines by +, add a 0 and send it to the Ruby interpreter?

(sed -e "s/$/+/" file; echo 0)|irb

If you do not have irb, you can send it to bc, but you have to remove all newlines except the last one (of echo). It is better to use tr for this, unless you have a PhD in sed .

(sed -e "s/$/+/" file|tr -d "\n"; echo 0)|bc

GNU Parallel can presumably be used to improve many of the above answers by spreading the workload across multiple cores.

In the example below we send chunks of 500 numbers (--max-lines=500) to bc processes which are executed in parallel 4 at a time (-j 4). The results are then aggregated by a final bc.

time parallel --max-lines=500 -j 4 --pipe "paste -sd+ - | bc" < random_numbers | paste -sd+ - | bc

The optimal choice of work size and number of parallel processes depends on the machine and problem. Note that this solution only really shines when there's a large number of parallel processes with substantial work each.

I prefer to use GNU datamash for such tasks because it's more succinct and legible than perl or awk. For example

datamash sum 1 < myfile

where 1 denotes the first column of data.

C always wins for speed:

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv) {
    ssize_t read;
    char *line = NULL;
    size_t len = 0;
    double sum = 0.0;

    while (read = getline(&line, &len, stdin) != -1) {
        sum += atof(line);
    }

    printf("%f", sum);
    return 0;
}

Timing for 1M numbers (same machine/input as my python answer):

$ gcc sum.c -o sum && time ./sum < numbers 
5003371677.000000
real    0m0.188s
user    0m0.180s
sys     0m0.000s

Another for fun

sum=0;for i in $(cat file);do sum=$((sum+$i));done;echo $sum

or another bash only

s=0;while read l; do s=$((s+$l));done<file;echo $s

But awk solution is probably best as it's most compact.

You can do it with Alacon - command-line utility for Alasql database.

It works with Node.js, so you need to install Node.js and then Alasql package:

To calculate sum from TXT file you can use the following command:

> node alacon "SELECT VALUE SUM([0]) FROM TXT('mydata.txt')"

In Go:

package main

import (
    "bufio"
    "fmt"
    "os"
    "strconv"
)

func main() {
    scanner := bufio.NewScanner(os.Stdin)
    sum := int64(0)
    for scanner.Scan() {
        v, err := strconv.ParseInt(scanner.Text(), 10, 64)
        if err != nil {
            fmt.Fprintf(os.Stderr, "Not an integer: '%s'\n", scanner.Text())
            os.Exit(1)
        }
        sum += v
    }
    fmt.Println(sum)
}

cat nums | perl -ne '$sum += $_ } { print $sum'

(same as brian d foy's answer, without 'END')

This is straight Bash:

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

Another option is to use jq:

$ seq 10|jq -s add
55

-s (--slurp) reads the input lines into an array.

Here is a solution using python with a generator expression. Tested with a million numbers on my old cruddy laptop.

time python -c "import sys; print sum((float(l) for l in sys.stdin))" < file

real    0m0.619s
user    0m0.512s
sys     0m0.028s

Here's another:

open(FIL, "a.txt");

my $sum = 0;
foreach( <FIL> ) {chomp; $sum += $_;}

close(FIL);

print "Sum = $sum\n";

C++ "one-liner":

#include <iostream>
#include <iterator>
#include <numeric>
using namespace std;

int main() {
    cout << accumulate(istream_iterator<int>(cin), istream_iterator<int>(), 0) << endl;
}

I prefer to use R for this:

$ R -e 'sum(scan("filename"))'

I couldn't just pass by... Here's my Haskell one-liner. It's actually quite readable:

sum <$> (read <$>) <$> lines <$> getContents

Unfortunately there's no ghci -e to just run it, so it needs the main function, print and compilation.

main = (sum <$> (read <$>) <$> lines <$> getContents) >>= print

To clarify, we read entire input (getContents), split it by lines, read as numbers and sum. <$> is fmap operator - we use it instead of usual function application because sure this all happens in IO. read needs an additional fmap, because it is also in the list.

$ ghc sum.hs
[1 of 1] Compiling Main             ( sum.hs, sum.o )
Linking sum ...
$ ./sum 
1
2
4
^D
7

Here's a strange upgrade to make it work with floats:

main = ((0.0 + ) <$> sum <$> (read <$>) <$> lines <$> getContents) >>= print

$ ./sum 
1.3
2.1
4.2
^D
7.6000000000000005

$ perl -MList::Util=sum -le 'print sum <>' nums.txt

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

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;

Just for fun, let's benchmark it:

$ for ((i=0; i<1000000; i++)) ; do echo $RANDOM; done > random_numbers

$ time perl -nle '$sum += $_ } END { print $sum' random_numbers
16379866392

real    0m0.226s
user    0m0.219s
sys     0m0.002s

$ time awk '{ sum += $1 } END { print sum }' random_numbers
16379866392

real    0m0.311s
user    0m0.304s
sys     0m0.005s

$ time { { tr "\n" + < random_numbers ; echo 0; } | bc; }
16379866392

real    0m0.445s
user    0m0.438s
sys     0m0.024s

$ time { s=0;while read l; do s=$((s+$l));done<random_numbers;echo $s; }
16379866392

real    0m9.309s
user    0m8.404s
sys     0m0.887s

$ time { s=0;while read l; do ((s+=l));done<random_numbers;echo $s; }
16379866392

real    0m7.191s
user    0m6.402s
sys     0m0.776s

$ time { sed ':a;N;s/\n/+/;ta' random_numbers|bc; }
^C

real    4m53.413s
user    4m52.584s
sys 0m0.052s

I aborted the sed run after 5 minutes

I've been diving to lua, and it is speedy:

$ time lua -e 'sum=0; for line in io.lines() do sum=sum+line end; print(sum)' < random_numbers
16388542582.0

real    0m0.362s
user    0m0.313s
sys     0m0.063s

and while I'm updating this, ruby:

$ time ruby -e 'sum = 0; File.foreach(ARGV.shift) {|line| sum+=line.to_i}; puts sum' random_numbers
16388542582

real    0m0.378s
user    0m0.297s
sys     0m0.078s

Heed Ed Morton's advice: using $1

$ time awk '{ sum += $1 } END { print sum }' random_numbers
16388542582

real    0m0.421s
user    0m0.359s
sys     0m0.063s

vs using $0

$ time awk '{ sum += $0 } END { print sum }' random_numbers
16388542582

real    0m0.302s
user    0m0.234s
sys     0m0.063s

None of the solution thus far use paste. Here's one:

paste -sd+ filename | bc

As an example, calculate Sn where 1<=n<=100000:

$ seq 100000 | paste -sd+ | bc -l
5000050000

(For the curious, seq n would print a sequence of numbers from 1 to n given a positive number n.)

Perl 6

say sum lines

~$ perl6 -e '.say for 0..1000000' > test.in

~$ perl6 -e 'say sum lines' < test.in
500000500000

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...

Just to be ridiculous:

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

With Ruby:

ruby -e "File.read('file.txt').split.inject(0){|mem, obj| mem += obj.to_f}"

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.

Running R scripts

I've written an R script to take arguments of a file name and sum the lines.

#! /usr/local/bin/R
file=commandArgs(trailingOnly=TRUE)[1]
sum(as.numeric(readLines(file)))

This can be sped up with the "data.table" or "vroom" package as follows:

#! /usr/local/bin/R
file=commandArgs(trailingOnly=TRUE)[1]
sum(data.table::fread(file))

#! /usr/local/bin/R
file=commandArgs(trailingOnly=TRUE)[1]
sum(vroom::vroom(file))

Benchmarking

Same benchmarking data as @glenn jackman.

for ((i=0; i<1000000; i++)) ; do echo $RANDOM; done > random_numbers

In comparison to the R call above, running R 3.5.0 as a script is comparable to other methods (on the same Linux Debian server).

$ time R -e 'sum(scan("random_numbers"))'  
 0.37s user
 0.04s system
 86% cpu
 0.478 total

R script with readLines

$ time Rscript sum.R random_numbers
  0.53s user
  0.04s system
  84% cpu
  0.679 total

R script with data.table

$ time Rscript sum.R random_numbers     
 0.30s user
 0.05s system
 77% cpu
 0.453 total

R script with vroom

$ time Rscript sum.R random_numbers     
  0.54s user 
  0.11s system
  93% cpu
  0.696 total

Comparison with other languages

For reference here as some other methods suggested on the same hardware

Python 2 (2.7.13)

$ time python2 -c "import sys; print sum((float(l) for l in sys.stdin))" < random_numbers 
 0.27s user 0.00s system 89% cpu 0.298 total

Python 3 (3.6.8)

$ time python3 -c "import sys; print(sum((float(l) for l in sys.stdin)))" < random_number
0.37s user 0.02s system 98% cpu 0.393 total

Ruby (2.3.3)

$  time ruby -e 'sum = 0; File.foreach(ARGV.shift) {|line| sum+=line.to_i}; puts sum' random_numbers
 0.42s user
 0.03s system
 72% cpu
 0.625 total

Perl (5.24.1)

$ time perl -nle '$sum += $_ } END { print $sum' random_numbers
 0.24s user
 0.01s system
 99% cpu
 0.249 total

Awk (4.1.4)

$ time awk '{ sum += $0 } END { print sum }' random_numbers
 0.26s user
 0.01s system
 99% cpu
 0.265 total
$ time awk '{ sum += $1 } END { print sum }' random_numbers
 0.34s user
 0.01s system
 99% cpu
 0.354 total

C (clang version 3.3; gcc (Debian 6.3.0-18) 6.3.0 )

 $ gcc sum.c -o sum && time ./sum < random_numbers   
 0.10s user
 0.00s system
 96% cpu
 0.108 total

Update with additional languages

Lua (5.3.5)

$ time lua -e 'sum=0; for line in io.lines() do sum=sum+line end; print(sum)' < random_numbers 
 0.30s user 
 0.01s system
 98% cpu
 0.312 total

tr (8.26) must be timed in bash, not compatible with zsh

$time { { tr "\n" + < random_numbers ; echo 0; } | bc; }
real    0m0.494s
user    0m0.488s
sys 0m0.044s

sed (4.4) must be timed in bash, not compatible with zsh

$  time { head -n 10000 random_numbers | sed ':a;N;s/\n/+/;ta' |bc; }
real    0m0.631s
user    0m0.628s
sys     0m0.008s
$  time { head -n 100000 random_numbers | sed ':a;N;s/\n/+/;ta' |bc; }
real    1m2.593s
user    1m2.588s
sys     0m0.012s

note: sed calls seem to work faster on systems with more memory available (note smaller datasets used for benchmarking sed)

Julia (0.5.0)

$ time julia -e 'print(sum(readdlm("random_numbers")))'
 3.00s user 
 1.39s system 
 136% cpu 
 3.204 total
$  time julia -e 'print(sum(readtable("random_numbers")))'
 0.63s user 
 0.96s system 
 248% cpu 
 0.638 total

Notice that as in R, file I/O methods have different performance.

One in tcl:

#!/usr/bin/env tclsh
set sum 0
while {[gets stdin num] >= 0} { incr sum $num }
puts $sum