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 pq
  43 .Op Fl h Ar hostname
  44 .Op Ar user
  45 .Nm login
  46 .Fl f
  47 .Op Fl lpq
  48 .Op Fl h Ar hostname
  49 .Op Ar user Op Ar prog Op Ar args...
  50 .Sh DESCRIPTION
  51 The
  52 .Nm login
  53 utility logs users (and pseudo-users) into the computer system.
  54 .Pp
  55 If no user is specified, or if a user is specified and authentication
  56 of the user fails,
  57 .Nm login
  58 prompts for a user name.
  59 Authentication of users is done via passwords.
  60 .Pp
  61 The options are as follows:
  62 .Bl -tag -width Ds
  63 .\" ==========
  64 .It Fl f
  65 The
  66 .Fl f
  67 option is used when a user name is specified to indicate that proper
  68 authentication has already been done and that no password need be
  69 requested.
  70 This option may only be used by the super-user or when an already
  71 logged in user is logging in as themselves.
  72 .Pp
  73 With the
  74 .Fl f
  75 option, an alternate program (and any arguments) may be run instead of the
  76 user's default shell.
  77 The program and arguments follows the user name.
  78 .\" ==========
  79 .It Fl h
  80 The
  81 .Fl h
  82 option specifies the host from which the connection was received.
  83 It is used by various daemons such as
  84 .Xr telnetd  8 .
  85 This option may only be used by the super-user.
  86 .\" ==========
  87 .It Fl l
  88 Tells the program executed by
  89 .Nm login
  90 that this is not a login session (by convention, a login session is
  91 signalled to the program with a hyphen as the first character of
  92 .Em argv[0] ;
  93 this option disables that), and prevents it from chdir(2)ing to the user's home directory.
  94 The default is to add the hyphen (this is a login session).
  95 .\" ==========
  96 .It Fl p
  97 By default,
  98 .Nm login
  99 discards any previous environment.
 100 The
 101 .Fl p
 102 option disables this behavior.
 103 .\" ==========
 104 .It Fl q
 105 This forces quiet logins, as if a
 106 .Pa .hushlogin
 107 is present.
 108 .El
 109 .Pp
 110 If the file
 111 .Pa /etc/nologin
 112 exists,
 113 .Nm login
 114 dislays its contents to the user and exits.
 115 This is used by
 116 .Xr shutdown  8
 117 to prevent users from logging in when the system is about to go down.
 118 .Pp
 119 Immediately after logging a user in,
 120 .Nm login
 121 displays the system copyright notice, the date and time the user last
 122 logged in, the message of the day as well as other information.
 123 If the file
 124 .Dq Pa .hushlogin
 125 exists in the user's home directory or
 126 .Fl q
 127 is specified, all of these messages are suppressed.
 128 This is to simplify logins for non-human users, such as
 129 .Xr uucp 1 .
 130 .Nm Login
 131 then records an entry in
 132 .Xr utmpx 5
 133 and the like, and executes the user's command interpreter (or the program
 134 specified on the command line if
 135 .Fl f
 136 is specified).
 137 .Pp
 138 Login enters information into the environment (see
 139 .Xr environ 7 )
 140 specifying the user's home directory (HOME), command interpreter (SHELL),
 141 search path (PATH), terminal type (TERM) and user name (both LOGNAME and
 142 USER).
 143 .Pp
 144 The standard shells,
 145 .Xr csh 1
 146 and
 147 .Xr sh 1 ,
 148 do not fork before executing the
 149 .Nm login
 150 utility.
 151 .Sh FILES
 152 .Bl -tag -width /var/mail/userXXX -compact
 153 .It Pa /etc/motd
 154 message-of-the-day
 155 .It Pa /etc/nologin
 156 disallows logins
 157 .It Pa /var/run/utmpx
 158 current logins
 159 .It Pa /var/mail/user
 160 system mailboxes
 161 .It Pa \&.hushlogin
 162 makes login quieter
 163 .El
 164 .Sh SEE ALSO
 165 .Xr chpass 1 ,
 166 .Xr passwd 1 ,
 167 .Xr rlogin 1 ,
 168 .Xr getpass 3 ,
 169 .Xr utmpx 5 ,
 170 .Xr environ 7
 171 .Sh HISTORY
 172 A
 173 .Nm login
 174 appeared in
 175 .At v6 .