Linux Combine two files by column

Question

I am trying to combine two files as below (Intersection)

ID     Name  Telephone       
1      John     011
2      Sam      013
3      Jena     014
4      Pet         


        

Answer 1

 awk -F"\t" '
     {key = $1 FS $2 FS $3 FS $4}
     NR == 1 {header = key}
     !(key in result) {result[key] = $0; next}
     { for (i=5; i <= NF; i++) result[key] = result[key] FS $i }
     END {
         print result[header]
         delete result[header]
         PROCINFO["sorted_in"] = "@ind_str_asc"    # if using GNU awk
         for (key in result) print result[key]
     }
 ' Test1.txt Test2.txt ... > result.txt