It takes real stones to suggest Unix utility code is better quality than Knuth's handicraft. And, not having looked into much of it. Unix code usually works well enough on unchallenging input.
By some indices (simplicity, documented-ness, accessibility {as in: I can read and understand it without learning more than one language's behavior vs. bash/C/several others}), Knuth wins hands-down.
By others (generality, speed of implementation) he does not.
It is normal to point out at this point that if correctness is not important to you, an overwhelmingly more quickly produced implementation is possible.
But my comment was on remarks claiming superior reliability for the Unix utilities, which you have not addressed.
What's your index of "better quality"?
By some indices (simplicity, documented-ness, accessibility {as in: I can read and understand it without learning more than one language's behavior vs. bash/C/several others}), Knuth wins hands-down.
By others (generality, speed of implementation) he does not.