NAME
login - sign on
SYNOPSIS
login [ -p ] [ username ]
login [ -p ] [ -h hostname ] [ -f ] [ username ]
DESCRIPTION
The login command is used when a user initially signs on. It
may
also be used at any time to change from one user to another.
This
case is the one summarized first above and described here.
See
"How to Get Started" (in the MachTen User’s
Guide) for how to
connect initially. The invocation of login for initial
sign-on is
made by a system program or server using the latter form of
the
command and is described below.
If 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.
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 ".hushlogin" file in his home directory;
this is mostly
used to make life easier for non-human users, such as
uucp.
Login initializes the user and
group IDs and the working directory,
then executes a command interpreter (usually 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 ("-").
Login also modifies the
environment 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.
If the file /etc/nologin exists,
login prints its contents on the
user’s terminal and exits, (root is still let in).
This is used by
shutdown(8) to stop users logging in when the system is
about to go
down.
Login is recognized by sh(1) and
csh(1) and executed directly
(without forking).
There are several additional
options to login for use at initial
login. With one exception, these options are available only
to the
superuser. The -h option is used by telnetd(8) and other
servers
to list the host from which the connection was received. The
-f
option is used with a username on the command line to
indicate that
proper authentication has already been done and that no
password
need be requested. This option may be used by the superuser
or by
the user specified on the command line.
FILES
/etc/utmp accounting
/usr/adm/wtmp accounting
/usr/spool/mail/* mail
/etc/motd message-of-the-day
/etc/passwd password file
/etc/nologin stops logins
.hushlogin makes login quieter
SEE ALSO
mail(1), passwd(1), rlogin(1), getpass(3), passwd(5),
utmp(5),
environ(7), init(8), getty(8), shutdown(8)
DIAGNOSTICS
"Login incorrect," if the name or the password is
bad.
"No Shell", "cannot open password file",
"no directory"
BUGS
An undocumented option, -r is used by the remote login
server,
rlogind(8) to force login to enter into an initial
connection
protocol.