1.\" $OpenBSD: login.1,v 1.34 2024/08/16 16:11:06 florian Exp $ 2.\" 3.\" Copyright (c) 1980, 1990, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)login.1 8.2 (Berkeley) 5/5/94 31.\" 32.Dd $Mdocdate: August 16 2024 $ 33.Dt LOGIN 1 34.Os 35.Sh NAME 36.Nm login 37.Nd log into the computer 38.Sh SYNOPSIS 39.Nm login 40.Op Fl fp 41.Op Fl h Ar hostname 42.Op Fl L Ar local-addr 43.Op Fl R Ar remote-addr 44.Op Fl u Ar username 45.Op Ar user 46.Sh DESCRIPTION 47The 48.Nm 49utility logs users (and pseudo-users) into the computer system. 50.Pp 51If no user is specified, or if a user is specified and authentication 52of the user fails, 53.Nm 54prompts for a user name. 55Authentication of users is normally done via passwords, though 56external authentication mechanisms may be used (see 57.Xr login.conf 5 ) . 58To specify the alternate authentication mechanism 59.Va style , 60the string 61.Pf : Va style 62is appended to the user name (i.e., 63.Ar user : Ns Va style ) . 64.Pp 65The options are as follows: 66.Bl -tag -width Ds 67.It Fl f 68The 69.Fl f 70option is used when a user name is specified to indicate that proper 71authentication has already been done and that no password need be 72requested. 73This option may only be used by the superuser. 74.It Fl h Ar hostname 75Specifies the host from which the connection was received. 76This option may only be used by the superuser. 77.It Fl L Ar local-addr 78The 79.Fl L 80option specifies the local address of a socket. 81This information is passed on to any classify script (see 82.Xr login.conf 5 ) . 83.It Fl p 84By default, 85.Nm 86discards any previous environment. 87The 88.Fl p 89option disables this behavior. 90.It Fl R Ar remote-addr 91The 92.Fl R 93option specifies the remote address of a socket. 94This information is passed on to any classify script (see 95.Xr login.conf 5 ) . 96.It Fl u Ar username 97Specifies the remote user that initiated the connection. 98This option may only be used by the superuser. 99.El 100.Pp 101If the file 102.Pa /etc/nologin 103exists (and the 104.Dq ignorenologin 105boolean is not set in the user's login class), 106.Nm 107displays its contents to the user and exits. 108This is used by 109.Xr shutdown 8 110to prevent users from logging in when the system is about to go down. 111.Pp 112If the file 113.Pa /etc/fbtab 114exists, 115.Nm 116changes the protection and ownership of certain devices specified in this 117file. 118.Pp 119If the file 120.Pa /var/log/failedlogin 121exists, 122.Nm 123will record failed login attempts in this file. 124.Pp 125Immediately after logging a user in, 126.Nm 127displays the system copyright notice, the date and time the user last 128logged in, the date and time of the last unsuccessful login (if the file 129.Pa /var/log/failedlogin 130exists), the message of the day as well as other information. 131If the file 132.Dq Pa .hushlogin 133exists in the user's home directory, all of these messages are suppressed. 134This is to simplify logins for non-human users. 135.Nm 136then records an entry in the 137.Xr wtmp 5 138and 139.Xr utmp 5 140files and executes the user's command interpreter. 141.Pp 142.Nm 143enters information into the environment (see 144.Xr environ 7 ) 145specifying the user's home directory 146.Pq Ev HOME , 147command interpreter 148.Pq Ev SHELL , 149search path 150.Pq Ev PATH , 151terminal type 152.Pq Ev TERM , 153and user name 154.Po both Ev LOGNAME and Ev USER 155.Pc . 156.Pp 157The standard shells, 158.Xr csh 1 159and 160.Xr sh 1 , 161do not fork before executing the 162.Nm 163utility. 164.Pp 165Note that if 166.Nm 167is invoked by a non-root user, it will execute 168.Xr su 1 169in 170.Nm 171emulation mode instead. 172.Sh ENVIRONMENT 173.Nm 174sets the following environment variables: 175.Bl -tag -width REMOTEHOST 176.It Ev HOME 177The user's home directory, as specified by the password database. 178.It Ev SHELL 179The user's shell, as specified by the password database. 180.It Ev TERM 181The user's terminal type, if it can be determined. 182.It Ev LOGNAME 183The user's login name. 184.It Ev USER 185Same as 186.Ev LOGNAME . 187.It Ev MAIL 188The user's mailbox. 189.It Ev REMOTEHOST 190The name of the host from which the user logged in, if the 191.Fl h 192flag was specified. 193.It Ev REMOTEUSER 194The name of the remote user who initiated the connection, if the 195.Fl u 196flag was specified. 197.El 198.Pp 199Other environment variables may be specified in 200.Pa /etc/login.conf 201via the 202.Dq setenv 203capability. 204.Sh FILES 205.Bl -tag -width /var/log/failedlogin -compact 206.It Pa /etc/fbtab 207changes device protections 208.It Pa /etc/login.conf 209login configuration 210.It Pa /etc/motd 211message-of-the-day 212.It Pa /etc/nologin 213disallows logins 214.It Pa /var/log/failedlogin 215failed login account records 216.It Pa /var/log/lastlog 217last login account records 218.It Pa /var/log/wtmp 219login account records 220.It Pa /var/mail/user 221system mailboxes 222.It Pa /var/run/utmp 223current logins 224.It Pa \&.hushlogin 225makes login quieter 226.El 227.Sh SEE ALSO 228.Xr chpass 1 , 229.Xr passwd 1 , 230.Xr su 1 , 231.Xr readpassphrase 3 , 232.Xr setusercontext 3 , 233.Xr fbtab 5 , 234.Xr login.conf 5 , 235.Xr utmp 5 , 236.Xr environ 7 237.Sh HISTORY 238A 239.Nm 240utility appeared in 241.At v2 . 242