Question

Looking to perform an inner join on two different text files. Basically I’m looking for the inner join equivalent of the GNU join program. Does such a thing exist? If not, an awk or sed solution would be most helpful, but my first choice would be a Linux command.

Here’s an example of what I’m looking to do

file 1:

0|Alien Registration Card LUA|Checklist Update
1|Alien Registration Card LUA|Document App Plan
2|Alien Registration Card LUA|SA Application Nbr
3|Alien Registration Card LUA|tmp_preapp-DOB
0|App - CSCE Certificate LUA|Admit Type
1|App - CSCE Certificate LUA|Alias 1
2|App - CSCE Certificate LUA|Alias 2
3|App - CSCE Certificate LUA|Alias 3
4|App - CSCE Certificate LUA|Alias 4

file 2:

Alien Registration Card LUA

Results:

0|Alien Registration Card LUA|Checklist Update
1|Alien Registration Card LUA|Document App Plan
2|Alien Registration Card LUA|SA Application Nbr
3|Alien Registration Card LUA|tmp_preapp-DOB

Answer 1

Should not the file2 contain LUA at the end?

If yes, you can still use join:

join -t'|' -12 <(sort -t'|' -k2 file1) file2