There's no standard "uname". While I suspect that all uname's probably do implement -n somewhat identically, you can't be certain because there is variance on other options across different implementations.
Therefor, I can't imagine what in the man page confused you. I don't mean that sarcastically - I mean that because I don't know what man page you read, I don't know why it was confusing.
For example, on my OS X box here, it says
Quote:
-n print the nodename (the nodename may be a name that the system is
known by to a communications network).
On a nearby BSD box, man is more terse.
Quote:
-n Write the name of the system to standard output.
A Linux box says:
Quote:
-n, --nodename
print the network node hostname
An old SCO box tries to be more helpful:
Quote:
-n
Print the hostname (formerly also known as the ``node name''); that is, the first part (up to the first "." character) of the hostname parameter.
But it's not just the man pages. Implementation is different also. That BSD box prints out everyhing:
So does the Mac:
A SCO box:
And that's just -n, which is fairly dependable. Move into other flags and things can get very different.