> The first couple of lines in the trace seem to be pretty clearly related to setting up the sudo part of the command.

This is not correct. "sudo dtruss" makes sudo run dtruss, so it is not possible for dtruss to track what sudo is doing. You can see what "sudo" does (which is much more complicated) by running "sudo dtruss sudo". You need sudo twice because sudo is a setuid program, and obviously it would be insecure to allow anybody to trace a setuid program (for example, it has to read the shadow file, so if you could trace it then you could dump all the hashes and crack them on your own time).

On a separate note, it's probably a bad idea to go reading Linux man pages and expect those to give you accurate information about Mac system calls.