Are you one of those people who take everything literally, so any and all jokes fly far over their heads?
This rule of ten lines or less is clearly meant as an illustrative guideline. Obviously if you have a shell script that has 11 lines, but does what it has to do reliably, nobody will be bothered.
The idea that the rule is trying to convey is "don't write long, complex programs in shell". Arguing about exact numbers or wording here is detracting from the topic at hand.
