Here and to some extent above, I don't think we can just print "*line"; there may be additional data beyond "rest" that we'd also output.
This is already happening in various other places. See for example how the `probe` command is parsed. I guess the point of view is that the shader runner is a developer-facing tool, so we prefer a simpler code even if it results in somewhat less polished error messages.
We may also want to make sure "*rest" is either '\0' or a whitespace character.
Ok, that makes sense.