LOGIN(1)

NAME
login - sign on

SYNOPSIS
login [ name ]
login -p
login -h hostname
login -f name

DESCRIPTION
login is used when signing onto a system. It can also be used to switch from one user to another at any time (most modern shells have support for this feature built into them, however). If an argument is not given, login prompts for the username. If the user is not root, and if /etc/nologin exists, the contents of of this file are printed to the screen, and the login is terminated. This is typically used to prevent logins when the system is being taken down. If the user is root, then the login must be occuring on a tty listed in /etc/securetty. Failures will be logged with the syslog facility. After these conditions are checked, the password will be requested and checks (if a password is required for this username). Ten attempts are allowed before login dies, but after the first three, the response starts to get very slow. Login failures are reported via the syslog facility. This facility is also used to report any successful root logins. If the file .hushlogin exists, then a "quiet" login is performed (this disables the checking of the checking of mail and the printing of the last login time and message of the day). Otherwise, if /var/log/lastlog exists, the last login time is printed (and the current login is recorded). Random administrative things, such as setting the UID and GID of the tty are performed. The TERM environment variable is preserved, if it exists (other environment variables are preserved if the -p option is used). Then the HOME, PATH, SHELL, TERM, MAIL, and LOGNAME environment variables are set. PATH defaults to /usr/local/bin:/bin:/usr/bin:. for normal users, and to /sbin:/bin:/usr/sbin:/usr/bin for root. Last, if this is not a "quiet" login, the message of the day is printed and the file with the user's name in /usr/spool/mail will be checked, and a message printed if it has non-zero length. The user's shell is then started. If no shell is specified for the user in /etc/passwd, then /bin/sh is used. If there is no directory specified in /etc/passwd, then / is used (the home directory is checked for the .hushlogin file described above).

OPTIONS

-p  Used by getty(8) to tell login not to destroy the environment

-f  Used to skip a second login authentication. This specifically does not work for root, and does not appear to work well under Linux.

-h  Used by other servers (i.e., telnetd(8)) to pass the name of the remote host to login so that it may be placed in utmp and wtmp. Only the superuser may use this option.

FILES
/var/run/utmp
/var/log/wtmp
/var/log/lastlog
/usr/spool/mail/*
/etc/motd
/etc/passwd
/etc/nologin
/etc/usertty
.hushlogin

SEE ALSO
init(8), getty(8), mail(1), passwd(1), passwd(5), environ(7), shutdown(8)

BUGS
Linux, unlike other draconian operating systems, does not check quotas. The undocumented BSD -r option is not supported. This may be required by some rlogind(8) programs.

AUTHOR
Derived from BSD login 5.40 (5/9/89) by Michael Glad (glad@daimi.dk) for HP-UX
Ported to Linux 0.12: Peter Orbaek (poe@daimi.aau.dk)