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

It is far easier to use the join command:

$ cat a.txt 
ID     Name  Telephone       
1      John     011
2      Sam      013
3      Jena     014
4      Peter    015
$ cat b.txt 
ID     Remark1  Remark2       
1       Test1    Test2
2       Test3    Test4
3       Test5    Test6
4       Test7    Test8
5       Test7    Test8
6       Test7    Test8
7       Test7    Test8
8       Test7    Test8
9       Test7    Test8
$ join a.txt b.txt 
ID Name Telephone Remark1 Remark2
1 John 011 Test1 Test2
2 Sam 013 Test3 Test4
3 Jena 014 Test5 Test6
4 Peter 015 Test7 Test8

Use the column command to pretty print it:

$ join a.txt b.txt | column -t
ID  Name   Telephone  Remark1  Remark2
1   John   011        Test1    Test2
2   Sam    013        Test3    Test4
3   Jena   014        Test5    Test6
4   Peter  015        Test7    Test8