-.I login
-command
-is used when a user initially
-signs on, or it may be used at any time to change
-from one user to another.
-The latter case is the one summarized above and
-described here.
-See \*(lqHow to Get Started\*(rq for how to dial up initially.
-.PP
-If
-.I login
-is invoked without an argument,
-it asks for a user name, and, if
-appropriate, a password.
-Echoing is turned off (if possible) during the typing of the password,
-so it will not appear on the written record of the
-session.
-.PP
-After a successful login,
-accounting files are updated and
-the user is informed of the
-existence of mail.
-The message of the day is printed,
-as is the time of his last login.
-Both are suppressed if he has a \*(lq.hushlogin\*(rq
-file in his home directory; this
-is mostly used to make life easier for non-human users, such as
-.IR uucp .
-.PP
-.I Login
-initializes the user and group IDs and the working directory,
-then executes a command interpreter (usually
-.IR csh (1))
-according to specifications found in a password file.
-Argument 0 of the command interpreter is
-the name of the command interpreter with
-a leading dash (\*(lq\-\*(rq).
-.PP
-Login also modifies the
-environment
-.IR environ (7)
-with information specifying home directory, command interpreter, terminal
-type (if available) and user name.
-The `\-p' argument causes the remainder of the environment to be preserved,
-otherwise any previous environment is discarded.
-.PP
-If the file /etc/nologin exists,
-.I login
-prints its contents on the user's terminal and exits. This is
-used by
-.IR shutdown (8)
-to stop users logging in when the system is about to go down.
-.PP
-Login is recognized by
-.IR sh (1)
+.Fl f
+option is used when a user name is specified to indicate that proper
+authentication has already been done and that no password need be
+requested.
+This option may only be used by the super-user or when an already
+logged in user is logging in as themselves.
+.It Fl h
+The
+.Fl h
+option specifies the host from which the connection was received.
+It is used by various daemons such as
+.Xr telnetd 8 .
+This option may only be used by the super-user.
+.It Fl p
+By default,
+.Nm login
+discards any previous environment.
+The
+.Fl p
+option disables this behavior.
+.El
+.Pp
+If the file
+.Pa /etc/nologin
+exists,
+.Nm login
+dislays its contents to the user and exits.
+This is used by
+.Xr shutdown 8
+to prevent users from logging in when the system is about to go down.
+.Pp
+Immediately after logging a user in,
+.Nm login
+displays the system copyright notice, the date and time the user last
+logged in, the message of the day as well as other information.
+If the file
+.Dq Pa .hushlogin
+exists in the user's home directory, all of these messages are suppressed.
+This is to simplify logins for non-human users, such as
+.Xr uucp 1 .
+.Nm Login
+then records an entry in the
+.Xr wtmp 5
+and
+.Xr utmp 5
+files and executes the user's command interpretor.
+.Pp
+Login enters information into the environment (see
+.Xr environ 7 )
+specifying the user's home directory (HOME), command interpreter (SHELL),
+search path (PATH), terminal type (TERM) and user name (both LOGNAME and
+USER).
+.Pp
+The standard shells,
+.Xr csh 1