login(1) DG/UX 4.30 login(1)
NAME
login - sign on
SYNOPSIS
login [ name [ env-var ... ] ]
DESCRIPTION
The login command identifies you to the system. Generally,
the system is already running login when you first approach
it. An unoccupied terminal will be displaying
login:
Type your username, then press New Line. The system then
displays:
Password:
You type your password (it will not show on the screen). The
system will check your name and password, and either tell
you to try again (if an answer was wrong) or proceed to log
you in.
When you log out (by typing Control-D at the command line
prompt), the system prepares for the next user by running
the login program, showing the login: prompt on the screen.
If you invoke login from the command line, it must replace
the initial command interpreter. Type "exec login" from the
initial shell.
Login asks for your user name (if not supplied as an
argument), and, if appropriate, your password. Echoing is
turned off (where possible) while you type your password, so
it will not appear on the written record of the session.
At some installations, an option may be invoked that will
require you to enter a second ``dialup'' password. This
will occur only for dial-up connections, and will be
prompted by the message "dialup password:". Both passwords
are required. To use the dial-up password feature, the
dial-up device must have an entry in the /etc/dialups file.
The program you wish to use once logged in at the device
(such as a shell) must have an entry in the /etc/dpasswd
file that includes an encrypted password. This encrypted
password is the one you provide when you log into the dialup
device. See the dialups(5) and dpasswd(5) files for more
information.
If you do not complete the login successfully within one
minute, you are likely to be silently disconnected.
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login(1) DG/UX 4.30 login(1)
After a successful login, accounting files are updated and
the user ID, group ID, working directory, and command
interpreter (usually sh(1)) are initialized. If the
initialized command interpreter is sh, login instructs sh to
perform the procedure /etc/profile. In addition, if the
file .profile exists in the working directory, sh executes
it as well. These specifications are found in the
/etc/passwd file entry for the user. The name of the
command interpreter is - followed by the last component of
the interpreter's pathname (i.e., -sh). If this field in
the password file is empty, then the default command
interpreter /bin/sh is used. If this field is *, then a
chroot(2) is done to the directory named in the directory
field of the entry. At that point login is re-executed at
the new level which must have its own root structure,
including /etc/login and /etc/passwd.
The basic environment (see environ(5)) is initialized to:
HOME=your-login-directory
PATH=:/bin:/usr/bin
SHELL=last-field-of-passwd-entry
MAIL=/usr/mail/your-login-name
TZ=timezone-specification
You can change the environment 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 into 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 that are not restricted. Both login and
getty understand simple single-character enquoting
conventions. Typing a backslash in front of a character
quotes it and lets you include such things as spaces and
tabs.
FILES
/etc/utmp Accounting
/etc/wtmp Accounting
/usr/mail/your-name Mailbox for user your-name
/etc/motd Message-of-the-day
/etc/passwd Password file
/etc/profile System profile
.profile User's login profile
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login(1) DG/UX 4.30 login(1)
SEE ALSO
mail(1), newgrp(1), sh(1), su(1).
d_passwd(4), dialups(4), passwd(4), profile(4), environ(5)
in the Programmer's Reference for the DG/UX System (Part 2)
DIAGNOSTICS
login incorrect
This message appears if the user name or the password cannot
be matched.
No shell, cannot open password file, or no directory
If these messages appear consult your system administrator.
No utmp entry. You must exec login from the lowest level
sh.
This message appears if you attempted to execute login as a
command without using the shell's exec internal command or
from other than the initial shell.
Cannot open /dev/tty.
This message appears if login is unable to open /dev/tty to
read the password.
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