Oh, cool, I didn't know that.
But it doesn't do the string=string+"something" commands?
Just by the way, the program works now with the string, it was actually the settings on the serial monitor, I would never have considered that.
I had it set to both new line and carriage return, and I assume that it's entered as \r\n, so all my commands ended in \r.
But I will certainly try out the variant with char arrays, to see what works better in this instance.