Comment by meelooo

You are describing the problem exactly: it all too tempting to pass text around from user input to command line arguments without any way to validate the text data and assume it's ok because it's easy. It's exactly the same arguments that goes in between static and dynamic typing in programming languages: static typing ensures some sort of semantics is respected. If you pass text around, because it's easy and fast, most of the time you will never validate the data and you have no way to ensure that you are not actually handling a bomb. If the protocol was binary there is no way in hell you would be tempted to pass it's data without validation to an external program because you'd have to respect the API and because there would be not way to just send a bunch of commands. The same goes for sql injections, url buffer overflows, etc. Free form text should only be used for actual human textual data and should NEVER be the interface in between programs. It's way too fuzzily defined to serve as a protocol.