login(1) (Essential Utilities) login(1)
NAME
login - sign on
SYNOPSIS
login [ -d device ] [ name [ environ ... ]]
DESCRIPTION
The login command is used at the beginning of each terminal session
and allows you to identify yourself to the system. It may be invoked
as a command or by the system when a connection is first established.
It is invoked by the system when a previous user has terminated the
initial shell by typing a cntrl-d to indicate an end-of-file.
If login is invoked as a command it must replace the initial command
interpreter. This is accomplished by typing
exec login
from the initial shell.
login asks for your user name (if it is not supplied as an argument),
and if appropriate, your password. Echoing is turned off (where
possible) during the typing of your password, so it will not appear
on the written record of the session.
If there are no lower-case characters in the first line of input
processed, login assumes the connecting TTY is an upper-case-only
terminal and sets the port's termio(7) options to reflect this.
login accepts a device option, device. device is taken to be the
path name of the TTY port login is to operate on. The use of the
device option can be expected to improve login performance, since
login will not need to call ttyname(3).
If you make any mistake in the login procedure, the message
Login incorrect
is printed and a new login prompt will appear. If you make five
incorrect login attempts, all five may be logged in /var/adm/loginlog
(if it exists) and the TTY line will be dropped.
If you do not complete the login successfully within a certain period
of time (e.g., one minute), you are likely to be silently
disconnected.
After a successful login, accounting files are updated, the
/etc/profile script is executed, the time you last logged in is
printed, /etc/motd is printed, the user-ID, group-ID, supplementary
group list, working directory, and command interpreter (usually sh)
are initialized, and the file .profile in the working directory is
executed, if it exists. The name of the command interpreter is -
followed by the last component of the interpreter's path name (e.g.,
-sh). If this field in the password file is empty, then the default
command interpreter, /usr/bin/sh is used. If this field is *, then
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login(1) (Essential Utilities) login(1)
the named directory becomes the root directory, the starting point
for path searches for path names beginning with a /. At that point
login is re-executed at the new level which must have its own root
structure, including /var/adm/login and /etc/passwd.
The basic environment is initialized to:
HOME=your-login-directory
LOGNAME=your-login-name
PATH=/usr/bin
SHELL=last-field-of-passwd-entry
MAIL=/var/mail/your-login-name
TZ=timezone-specification
The environment may be expanded or modified by supplying additional
arguments to login, either at execution time or when login requests
your login name. The arguments may take either the form xxx or
xxx=yyy. Arguments without an equal sign are placed in the
environment as
Ln=xxx
where n is a number starting at 0 and is incremented each time a new
variable name is required. Variables containing an = are placed in
the environment without modification. If they already appear in the
environment, then they replace the older value. There are two
exceptions. The variables PATH and SHELL cannot be changed. This
prevents people, logging into restricted shell environments, from
spawning secondary shells which are not restricted. login understands
simple single-character quoting conventions. Typing a backslash in
front of a character quotes it and allows the inclusion of such
characters as spaces and tabs.
FILES
/var/adm/utmp accounting
/var/adm/wtmp accounting
/var/mail/your-name mailbox for user your-name
/var/adm/loginlog record of failed login attempts
/etc/motd message-of-the-day
/etc/passwd password file
/etc/profile system profile
.profile user's login profile
/var/adm/lastlog time of last login
SEE ALSO
mail(1), newgrp(1M), sh(1), su(1M).
loginlog(4), passwd(4), profile(4), environ(5) in the Programmer's
Reference Manual.
DIAGNOSTICS
login incorrect if the user name or the password cannot be matched.
No shell, cannot open password file, or no directory: consult a
system engineer.
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login(1) (Essential Utilities) login(1)
No utmp entry. You must exec "login" from the lowest level "sh" if
you attempted to execute login as a command without using the shell's
exec internal command or from a shell other than the initial shell.
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