NAME

login — authenticate users and run personal session

SYNOPSIS

login

DESCRIPTION

login interactively authenticates users by asking them to enter their username and password. The passwords are checked against the password hashes in /etc/passwd as described in passwd(5). login creates a session as the requested user upon successful authentication. login has a graphical interface if the display is graphical and uses a textual interface otherwise. The textual interface is forced if /etc/login.conf.textual exists. The process remains running in the background and takes over again when the user session exits. The user's session(5) is created upon login by running the user's ~/.session script if it exists and is executable, otherwise attempting /etc/session, and ultimately falling back on the user's shell from passwd(5). It can be overriden by suffixing the username with a colon and the name of the program to launch. If the program name is skipped, the login shell is launched. Type a special username to perform special options:

exit

alias for poweroff

poweroff

exit asking for powering off the computer

reboot

exit asking for rebooting the computer

halt

exit asking for halting the computer

reinit

exit asking for reinitializing the system

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 login program and trick the next user into revealing their password.

ENVIRONMENT

login sets the following environment variables to match the authenticated user:

HOME

home directory

LOGNAME

username

SHELL

shell

USER

username

FILES

~/.session

user session script run upon login (see session(5))

/etc/login.conf.textual

textual interface is forced if this file exists

/etc/passwd

user database (see passwd(5))

/etc/session

fallback session script run upon login (see session(5))

/var/run/nologin

Further non-privileged logins are prohibited if this file exists and users attempting to log in are shown the contents of this file (see shutdown(8))

EXIT STATUS

login exits 0 if the computer should power off, exits 1 if the computer should reboot, exits 2 on fatal failure and the boot should halt, or exits 3 if the system should reinitialize.

SEE ALSO

passwd(1), crypt_checkpass(3), passwd(5), session(5), init(8), shutdown(8)

BUGS

login only supports a single monitor. The mouse code is less than perfect.