login.1   [plain text]


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.\"	@(#)login.1	8.2 (Berkeley) 5/5/94
.\" $FreeBSD: src/usr.bin/login/login.1,v 1.33 2007/11/30 11:02:36 philip Exp $
.\"
.Dd September 13, 2006
.Dt LOGIN 1
.Os
.Sh NAME
.Nm login
.Nd log into the computer
.Sh SYNOPSIS
.Nm
.Op Fl pq
.Op Fl h Ar hostname
.Op Ar user
.Nm
.Fl f
.Op Fl lpq
.Op Fl h Ar hostname
.Op Ar user Op Ar prog Op Ar args...
.Sh DESCRIPTION
The
.Nm
utility logs users (and pseudo-users) into the computer system.
.Pp
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.
.Pp
The following options are available:
.Bl -tag -width indent
.It 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.
.Pp
With the
.Fl f
option, an alternate program (and any arguments) may be run instead of the
user's default shell.
The program and arguments follows the user name.
.It Fl h
Specify the host from which the connection was received.
It is used by various daemons such as
.Xr telnetd 8 .
This option may only be used by the super-user.
.It Fl l
Tells the program executed by
.Nm
that this is not a login session (by convention, a login session is
signalled to the program with a hyphen as the first character of
.Em argv[0] ;
this option disables that), and prevents it from chdir(2)ing to the user's home directory.
The default is to add the hyphen (this is a login session).
.It Fl p
By default,
.Nm
discards any previous environment.
The
.Fl p
option disables this behavior.
.It Fl q
This forces quiet logins, as if a
.Pa .hushlogin
is present.
.El
.Pp
If the file
.Pa /etc/nologin
exists,
.Nm
dislays its contents to the user and exits.
This is used by
.Xr shutdown  8
to prevent users from logging in when the system is about to go down.
.Pp
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
.Pa .hushlogin
exists in the user's home directory, all of these messages are suppressed.
.Fl q
is specified, all of these messages are suppressed.
This is to simplify logins for non-human users, such as
.Xr uucp 1 .
.Nm
then records an entry in
.Xr utmpx 5
and the like, and executes the user's command interpreter (or the program
specified on the command line if
.Fl f
is specified).
.Pp
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).
.Pp
Some shells may provide a builtin
.Nm
command which is similar or identical to this utility.
Consult the
.Xr builtin 1
manual page.
.Pp
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
.Bl -tag -width /var/mail/userXXX -compact
.It Pa /etc/motd
message-of-the-day
.It Pa /etc/nologin
disallows logins
.It Pa /var/run/utmpx
current logins
.It Pa /var/mail/user
system mailboxes
.It Pa \&.hushlogin
makes login quieter
.It Pa /etc/pam.d/login
.Xr pam 8
configuration file
.It Pa /etc/security/audit_user
user flags for auditing
.It Pa /etc/security/audit_control
global flags for auditing
.El
.Sh SEE ALSO
.Xr builtin 1 ,
.Xr chpass 1 ,
.Xr newgrp 1 ,
.Xr passwd 1 ,
.Xr rlogin 1 ,
.Xr getpass 3 ,
.Xr utmpx 5 ,
.Xr environ 7
.Sh HISTORY
A
.Nm
utility appeared in
.At v6 .