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 will be invoked 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 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:   con-
sult a system engineer.
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.