Matching data to correct ID from two files in awk

Question

I am trying to combine data from two different files. In each file, some data is linked to some ID. I want to \'combine\' both files in the sense that all ID\'s mus

Answer 1

Does it have to be awk, or did you choose this because you think that's the best - easiest way?

You can do this via join

$join -j 1 -a 1 -a 2 -o auto file_1 file_2 | column -t -s' ' -o' '
1.01 data_a data_aa
1.02 data_b
1.03 data_c data_cc
1.04 data_d
1.05 data_e data_ee
1.06 data_f
1.09        data_ii

edit: As per the excellent suggestion from KamilCuk you can preserve the output afterwards.