My first thought is that when I type a response, it does not look like this:
MyfirstthoughtisthatwhenItypearesponseitdoesnotlooklikethis:
So, then I wonder why you jam stuff together. Much simpler to parse things when there are delimiters.
If you were sending stuff like:
001 test string for the LCD
you would easily parse the arguments. That's what the strtok() function is made for.