Thanks for the comment.

When I wrote this example it never occurred to me that it could be confusing, but now you point it out, yes it is. I think I was keen to show that -F on the command line is the variable FS in the script, and having just shown an example of -F "," just continued to use it!

I was also keen to make it clear that the comma in a print statement is where Awk puts the contents of OFS, so I guess I lost sight of the example a little in my enthusiasm :-)

I will consider modifying these notes in the light of your suggestion.