So I have two csv files that have a common key. gnu join by itself can produce lines of output for records which have a common key.
What I would love to have happen, however, is when I use the -a 1 -a 2 , the program produce -e's values for each field of the merged output for the missing line in the file.
In other words
joined together with -a 1 -a 2 -e'""' currently produces
a 1 2
c 4 6
but lines b and d should have 3 fields, not 2 fields….