Definitely not. One can tell a naive, non-Unix programmer by the fact that they write code that pollutes the output of a command line utility with information

Definitely not. One can tell a naive, non-Unix programmer by the fact that they write code that pollutes the output of a command line utility with informational/ error garbage. (And it almost goes without saying that much real work still happens on the command line.) Regarding the OP comment about not being able to tell correspondence between a given output and an error: That is an interesting point, but generally in the Unix command line idiom, one stops the program on the first error, so it is easy to tell. However, if you have process that can't stop (like a server), then one has to be more careful and should probably use a more general logging system.