Even the traditional Unix tools don't follow the Unix Philosophy extremely well. ls is a prime example: It has too many ways to sort and format its output. It "should", in the Unix Philosophy sense, simply list things in a directory and leave sorting and formatting to other tools.

However, parsing the output of ls is generally a bad idea, as it's meant for human consumption, so ls breaks another tenet: It isn't very composable, as it is difficult to use it in a pipeline, even though it should be a prototypical source program.