[p4] Checking that a server exists?

[Gross, Steve]

What's the easiest way to use p4 to determine if a server exists? For
instance, consider this statement:
  p4 -p someServerName depots

If someServerName exists, p4 should list the depots in it, right?

I've tried this approach, but p4 responds:
  Perforce password (P4PASSWD) invalid or unset.

I've tried to login (successfully), as well as specify the client and/or
password on the command line. This has not worked, so far.

Any ideas?

Thanks,
--Steve