Thanks! To answer your questions... > because it makes it easier to see how it corresponds to actual Set Theory/theorems? Yes. These are the Unicode symbols f

Thanks! To answer your questions... > because it makes it easier to see how it corresponds to actual Set Theory/theorems? Yes. These are the Unicode symbols for set theory. > could you just as well have used an alphanummeric identifier like "left" "union" "right" or Yes. You can use any of the words in the case switch statements, such as `setop union file1 file2`. You can also edit the script to add your own words if you like. You can see simpler versions of these scripts in our GitHub repos. For example the `union` command is https://github.com/sixarm/union https://github.com/sixarm/union > set theory seems to pop up a lot in my line of work More and more in mine too. Thank you for your comments!