The Regents of the University of California. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. Neither the name of the University nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
.Dd September 29, 2022 .Dt LOGIN 1 .Os .Sh NAME .Nm login .Nd log into the computer .Sh SYNOPSIS .Nm .Op Fl fp .Op Fl h Ar hostname .Op Ar user .Sh DESCRIPTION The .Nm utility logs users (and pseudo-users) into the computer system.
p If no user is specified, or if a user is specified and authentication of the user fails, .Nm prompts for a user name. Authentication of users is configurable via .Xr pam 8 . Password authentication is the default.
p The following options are available: l -tag -width indent t Fl f When a user name is specified, this option indicates that proper authentication has already been done and that no password need be requested. This option may only be used by the super-user or when an already logged in user is logging in as themselves. t Fl h Specify the host from which the connection was received. It is used by various daemons such as .Nm telnetd . This option may only be used by the super-user. t Fl p By default, .Nm discards any previous environment. The .Fl p option disables this behavior. .El
p Login access can be controlled via .Xr login.access 5 or the login class in .Xr login.conf 5 , which provides allow and deny records based on time, tty and remote host name.
p If the file
a /etc/fbtab exists, .Nm changes the protection and ownership of certain devices specified in this file.
p Immediately after logging a user in, .Nm displays the system copyright notice, the date and time the user last logged in, the message of the day as well as other information. If the file
a .hushlogin exists in the user's home directory, all of these messages are suppressed. This is to simplify logins for non-human users, such as .Xr uucp 1 .
p The .Nm utility enters information into the environment (see .Xr environ 7 ) specifying the user's home directory (HOME), command interpreter (SHELL), search path (PATH), terminal type (TERM) and user name (both LOGNAME and USER). Other environment variables may be set due to entries in the login class capabilities database, for the login class assigned in the user's system passwd record. The login class also controls the maximum and current process resource limits granted to a login, process priorities and many other aspects of a user's login environment.
p Some shells may provide a builtin .Nm command which is similar or identical to this utility. Consult the .Xr builtin 1 manual page.
p The .Nm utility will submit an audit record when login succeeds or fails. Failure to determine the current auditing state will result in an error exit from .Nm . .Sh FILES l -tag -width ".Pa /etc/security/audit_control" -compact t Pa /etc/fbtab changes device protections t Pa /etc/login.conf login class capabilities database t Pa /var/run/motd message-of-the-day t Pa /var/mail/user system mailboxes t Pa .hushlogin makes login quieter t Pa /etc/pam.d/login .Xr pam 8 configuration file t Pa /etc/security/audit_user user flags for auditing t Pa /etc/security/audit_control global flags for auditing .El .Sh SEE ALSO .Xr builtin 1 , .Xr chpass 1 , .Xr csh 1 , .Xr newgrp 1 , .Xr passwd 1 , .Xr rlogin 1 , .Xr getpass 3 , .Xr fbtab 5 , .Xr login.access 5 , .Xr login.conf 5 , .Xr environ 7 .Sh HISTORY A .Nm utility appeared in .At v6 .