userinfo —
displays user information
The userinfo utility retrieves the user information from
  the system. The userinfo utility is only available if
  built with EXTENSIONS. See
  user(8) for more information.
The following command line option is recognised:
  - -e
- Return 0 if the user exists, and non-zero if the user does not exist, on
      the system. No information is displayed. This form of the command is
      useful for scripts which need to check whether a particular user name or
      uid is already in use on the system.
The user argument may either be a user's
    name, or a uid.
The userinfo utility exits 0 on success,
  and >0 if an error occurs.
The userinfo utility first appeared in
  NetBSD 1.5. It is based on the
  addnerd package by the same author.
The userinfo utility was written by
  Alistair G. Crooks ⟨agc@NetBSD.org⟩.