Shell Programming and Scripting

I have around 1000 files in a directory (file1.txt, file2.txt, ... file1000.txt), each file is 2 columns, the first colums are same for all of them, second one is different.

file1.txt
1 10
2 20
3 30
4 40
5 50

file2.txt
1 100
2 400
3 500
4 600
5 900

what I need is , I want output.txt such as for only 2 above files, it will give
output.txt
1 110
2 420
3 530
4 640
5 950

well if there was only two files i could do

Code:

pr -m -t -s\  *txt | gawk '{print  $1,$2+$4}'

but I have thousand files , I need sth like

Code:

pr -m -t -s\  *txt | gawk '{print  $1,$2+$4+...+$2000}'

also I want to make it dynamic (number of files may change)

what I tried is

Code:

#!/bin/bash

numfiles=$(ls *.txt | wc -l)
command=""

for (( c=1; c<=$numfiles; c++ ))
do  
command=" ${command}\$$[2*${c}]+"
pr -m -t -s\  *trace | gawk '{print $1,${command}}'
done

Code:

join file file2| awk '{t=0;for(i=2;i<=NF;i++){t+=$i};print $1,t}'

Not sure how are you going to distinguish the two files.Or is it going to be file1 and file2 all the time??

Anyway, try the below logic to add the second column

Code:

awk '{ A[$1]+=$2;} END{ for (i in A) print i" "A[i]; }' file1 file2 | sort -nk1 -o out.txt

thanks guys