login.tproj/login.1

   1 .\" Copyright (c) 1980, 1990, 1993
   2 .\"     The Regents of the University of California.  All rights reserved.
   3 .\"
   4 .\" Redistribution and use in source and binary forms, with or without
   5 .\" modification, are permitted provided that the following conditions
   6 .\" are met:
   7 .\" 1. Redistributions of source code must retain the above copyright
   8 .\"    notice, this list of conditions and the following disclaimer.
   9 .\" 2. Redistributions in binary form must reproduce the above copyright
  10 .\"    notice, this list of conditions and the following disclaimer in the
  11 .\"    documentation and/or other materials provided with the distribution.
  12 .\" 3. All advertising materials mentioning features or use of this software
  13 .\"    must display the following acknowledgement:
  14 .\"     This product includes software developed by the University of
  15 .\"     California, Berkeley and its contributors.
  16 .\" 4. Neither the name of the University nor the names of its contributors
  17 .\"    may be used to endorse or promote products derived from this software
  18 .\"    without specific prior written permission.
  19 .\"
  20 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30 .\" SUCH DAMAGE.
  31 .\"
  32 .\"     @(#)login.1     8.2 (Berkeley) 5/5/94
  33 .\"
  34 .Dd May 5, 1994
  35 .Dt LOGIN 1
  36 .Os BSD 4
  37 .Sh NAME
  38 .Nm login
  39 .Nd log into the computer
  40 .Sh SYNOPSIS
  41 .Nm login
  42 .Op Fl fp
  43 .Op Fl h Ar hostname
  44 .Op Ar user
  45 .Sh DESCRIPTION
  46 The
  47 .Nm login
  48 utility logs users (and pseudo-users) into the computer system.
  49 .Pp
  50 If no user is specified, or if a user is specified and authentication
  51 of the user fails,
  52 .Nm login
  53 prompts for a user name.
  54 Authentication of users is done via passwords.
  55 .Pp
  56 The options are as follows:
  57 .Bl -tag -width Ds
  58 .It Fl f
  59 The
  60 .Fl f
  61 option is used when a user name is specified to indicate that proper
  62 authentication has already been done and that no password need be
  63 requested.
  64 This option may only be used by the super-user or when an already
  65 logged in user is logging in as themselves.
  66 .It Fl h
  67 The
  68 .Fl h
  69 option specifies the host from which the connection was received.
  70 It is used by various daemons such as
  71 .Xr telnetd  8 .
  72 This option may only be used by the super-user.
  73 .It Fl p
  74 By default,
  75 .Nm login
  76 discards any previous environment.
  77 The
  78 .Fl p
  79 option disables this behavior.
  80 .El
  81 .Pp
  82 If the file
  83 .Pa /etc/nologin
  84 exists,
  85 .Nm login
  86 dislays its contents to the user and exits.
  87 This is used by
  88 .Xr shutdown  8
  89 to prevent users from logging in when the system is about to go down.
  90 .Pp
  91 Immediately after logging a user in,
  92 .Nm login
  93 displays the system copyright notice, the date and time the user last
  94 logged in, the message of the day as well as other information.
  95 If the file
  96 .Dq Pa .hushlogin
  97 exists in the user's home directory, all of these messages are suppressed.
  98 This is to simplify logins for non-human users, such as
  99 .Xr uucp 1 .
 100 .Nm Login
 101 then records an entry in the
 102 .Xr wtmp 5
 103 and
 104 .Xr utmp 5
 105 files and executes the user's command interpretor.
 106 .Pp
 107 Login enters information into the environment (see
 108 .Xr environ 7 )
 109 specifying the user's home directory (HOME), command interpreter (SHELL),
 110 search path (PATH), terminal type (TERM) and user name (both LOGNAME and
 111 USER).
 112 .Pp
 113 The standard shells,
 114 .Xr csh 1
 115 and
 116 .Xr sh 1 ,
 117 do not fork before executing the
 118 .Nm login
 119 utility.
 120 .Sh FILES
 121 .Bl -tag -width /var/mail/userXXX -compact
 122 .It Pa /etc/motd
 123 message-of-the-day
 124 .It Pa /etc/nologin
 125 disallows logins
 126 .It Pa /var/run/utmp
 127 current logins
 128 .It Pa /var/log/lastlog
 129 last login account records
 130 .It Pa /var/log/wtmp
 131 login account records
 132 .It Pa /var/mail/user
 133 system mailboxes
 134 .It Pa \&.hushlogin
 135 makes login quieter
 136 .El
 137 .Sh SEE ALSO
 138 .Xr chpass 1 ,
 139 .Xr passwd 1 ,
 140 .Xr rlogin 1 ,
 141 .Xr getpass 3 ,
 142 .Xr utmp 5 ,
 143 .Xr environ 7 ,
 144 .Sh HISTORY
 145 A
 146 .Nm login
 147 appeared in
 148 .At v6 .