JD - I don't know of a solution within Tableau to add a single row text file to a data file. Even trying to open a single row text file results in error. Maybe my response will trigger another idea. Also - what about the cat command process you worked out creates an issue?
Hi Patrick, if you add a newline to the text file then Tableau will be ok with it, and that Null record could be easily filtered out.
I was curious and tried out the 9.3beta UNION functionality using a data set with 2 fields (header1 and header2) that had a newline, and then a couple of rows of data in the data.txt file with no header, here's what happened:
Tableau merged the data sets and ended up with 2 rows, so it ignored the Null row from the headers file. I don't think this is a solution because someone would have to manually rename fields or create a calculated field. Doing the work outside of Tableau to concatenate the two files is still the best option, I think.