.Dd October 6, 2015
.Dt LOGIN 8
.Os
.Sh NAME
.Nm login
.Nd authenticate users and run personal session
.Sh SYNOPSIS
.Nm login
.Sh DESCRIPTION
.Nm login
interactively authenticates users by asking them to enter their username and
password.
The passwords are checked against the password hashes in
.Pa /etc/passwd
as described in
.Xr passwd 5 .
.Nm login
creates a session as the requested user upon successful authentication.
.Pp
.Nm login
has a graphical interface if the display is graphical and uses a textual
interface otherwise.
The textual interface is forced if
.Pa /etc/login.conf.textual
exists.
The process remains running in the background and takes over again when the user
session exits.
.Pp
Type a special username to perform special options:
.Pp
.Bl -tag -width "poweroff" -compact -offset indent
.It exit
alias for poweroff
.It poweroff
exit asking for powering off the computer
.It reboot
exit asking for rebooting the computer
.El
.Sh SECURITY
There is currently no method to confirm the login screen is in fact real other
than witnessing a pristine boot.
Local users can log in and show a counterfeit login screen that look and behave
like the real
.Nm login
program and trick the next user into revealing their password.
.Sh ENVIRONMENT
.Nm login
sets the following environment variables to match the authenticated user:
.Bl -tag -width "LOGNAME"
.It Ev HOME
home directory
.It Ev LOGNAME
username
.It Ev SHELL
shell
.It Ev USER
username
.El
.Sh FILES
.Bl -tag -width "/etc/passwd" -compact
.It Pa /etc/passwd
user database (see
.Xr passwd 5 )
.It Pa /etc/login.conf.textual
textual interface is forced if this file exists
.El
.Sh EXIT STATUS
.Nm login
exits 0 if the computer should power off, exits 1 if the computer should
reboot, or exits 2 on fatal failure and the boot should halt.
.Sh SEE ALSO
.Xr passwd 1 ,
.Xr crypt_checkpass 3 ,
.Xr passwd 5 ,
.Xr init 8 ,
.Xr login 8
.Sh BUGS
.Nm login
only supports a single monitor.
The mouse code is less than perfect.