135 lines
5.0 KiB
Groff
135 lines
5.0 KiB
Groff
.\" Copyright 1989 - 1994, Julianne Frances Haugh
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of Julianne F. Haugh nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $Id: login.1,v 1.6 1999/06/07 16:40:44 marekm Exp $
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.\"
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.TH LOGIN 1
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.SH NAME
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login \- Begin session on the system
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.SH SYNOPSIS
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.B login
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.RI [ username " [" environmental-variables ]]
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.\" XXX - document -f -h -p -r options
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.SH DESCRIPTION
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.B login
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is used to establish a new session with the system.
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It is normally invoked automatically by responding to the
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.I login:
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prompt on the user\'s terminal.
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.B login
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may be special to the shell and may not be invoked as a sub-process.
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Typically,
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.B login
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is treated by the shell as \fBexec login\fR which causes the user
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to exit from the current shell.
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Attempting to execute \fBlogin\fR from any shell but the login shell
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will produce an error message.
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.PP
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When invoked from the \fIlogin:\fR prompt, the user may enter
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environmental variables after the username.
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These variables are entered in the form \fBNAME=VALUE\fR.
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Not all variables may be set in the fashion, notably \fBPATH\fR,
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\fBHOME\fR and \fBSHELL\fR.
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Additionally, \fBIFS\fR may be inhibited if the user\'s login
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shell is \fB/bin/sh\fR.
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.PP
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The user is then prompted for a password, where appropriate.
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Echoing is disabled to prevent revealing the password.
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Only a small number of password failures are permitted before
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\fBlogin\fR exits and the communications link is severed.
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.PP
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If password aging has been enabled for your account, you may be
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prompted for a new password before proceeding.
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You will be forced to provide your old password and the new
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password before continuing.
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Please refer to \fBpasswd \fR(1) for more information.
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.PP
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After a successful login,
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you will be informed of any system messages and the presence
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of mail.
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You may turn off the printing of the system message file,
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\fI/etc/motd\fR, by creating a zero-length file \fI.hushlogin\fR
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in your login directory.
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The mail message will be one of "\fBYou have new mail.\fR",
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"\fBYou have mail.\fR", or "\fBNo Mail.\fR" according to
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the condition of your mailbox.
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.PP
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Your user and group ID will be set according to their values in
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the \fI/etc/passwd\fR file.
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The value for \fB$HOME\fR, \fB$SHELL\fR, \fB$PATH\fR, \fB$LOGNAME\fR,
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and \fB$MAIL\fR are set according to the appropriate fields in the
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password entry.
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Ulimit, umask and nice values may also be set according to
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entries in the GECOS field.
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.PP
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On some installations, the environmental variable \fB$TERM\fR will be
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initialize to the terminal type on your tty line, as specified in
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\fI/etc/ttytype\fR.
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.PP
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An initialization script for your command interpreter may also be
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executed.
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Please see the appropriate manual section for more information on
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this function.
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.SH CAVEATS
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.PP
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This version of \fBlogin\fR has many compilation options, only some of which
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may be in use at any particular site.
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.PP
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The location of files is subject to differences in system configuration.
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.SH FILES
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/etc/utmp \- list of current login sessions
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.br
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/etc/wtmp \- list of previous login sessions
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.br
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/etc/passwd \- user account information
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.br
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/etc/shadow \- encrypted passwords and age information
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.br
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/etc/motd \- system message file
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.br
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/etc/nologin \- prevent non-root users from logging in
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.br
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/etc/ttytype \- list of terminal types
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.br
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$HOME/.profile \- initialization script for default shell
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.br
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$HOME/.hushlogin \- suppress printing of system messages
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.br
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.SH SEE ALSO
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.PP
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.BR getty (8),
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.BR mail (1),
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.BR passwd (1),
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.BR sh (1),
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.BR su (1),
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.BR login.defs (5),
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.\" .BR d_passwd (5),
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.BR passwd (5),
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.BR nologin (5)
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.SH AUTHOR
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Julianne Frances Haugh (jfh@bga.com)
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