Shell Programming and Scripting

$ cat 1.txt 
x y z 1 2 3 4 5 6 7 8 9
a b c d e f 9 7 8 9 90 1
$ cat 2.txt 
x y z 2 4 5 6 7 8 1 0 0
a b c g h i 9 3 1 4 5 6
$ awk 'NR==FNR{a[$1,$2,$3]=$0; next} {printf a[$1,$2,$3]; $1=$2=$3=""; gsub(/^ */," ",$0); print $0}' 1.txt 2.txt
x y z 1 2 3 4 5 6 7 8 9 2 4 5 6 7 8 1 0 0
a b c d e f 9 7 8 9 90 1 g h i 9 3 1 4 5 6
$ cut -d" " -f4- 2.txt | paste -d" " 1.txt -
x y z 1 2 3 4 5 6 7 8 9 2 4 5 6 7 8 1 0 0
a b c d e f 9 7 8 9 90 1 g h i 9 3 1 4 5 6

awk 'NR==FNR{a[NR]=$0; next} {$1=$2=$3=""; gsub(/^ */," ",$0);  a[FNR]=a[FNR] $0}END{for(i=1; i<=FNR; i++) print a[i];}' *.txt

cp first.txt > out.txt
 for i in *.txt ; do 
   [[ "$i" = first.txt ]] && continue
   cut -d" " -f4- "$i" | paste -d" " out.txt - > tmpFile
   mv tmpFile out.txt
 done

#!/bin/bash
 
 function myPaste {
     if [[ $# -le 1 ]] ; then
        cat $1
        return
     fi
     arg=$1
     shift
 
     myPaste $* | cut -d" " -f4- | paste -d" " $arg -
 }
 
 myPaste $*

./myPaste.sh *.txt