LOGIN(1) BSD General Commands Manual LOGIN(1)
NAME
login -- log into the computer
SYNOPSIS
login [-pq] [-h hostname] [user]
login -f [-lpq] [-h hostname] [user [prog [args...]]]
DESCRIPTION
The login utility logs users (and pseudo-users) into the computer system.
If no user is specified, or if a user is specified and authentication of the user fails, login prompts
for a user name. Authentication of users is done via passwords.
The options are as follows:
-f The -f option is used when a user name is specified to indicate 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.
With the -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.
-h The -h option specifies the host from which the connection was received. It is used by various
daemons such as telnetd(8). This option may only be used by the super-user.
-l Tells the program executed by login 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 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).
-p By default, login discards any previous environment. The -p option disables this behavior.
-q This forces quiet logins, as if a .hushlogin is present.
If the file /etc/nologin exists, login dislays its contents to the user and exits. This is used by
shutdown(8) to prevent users from logging in when the system is about to go down.
Immediately after logging a user in, login 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 ``.hushlogin''
exists in the user's home directory or -q is specified, all of these messages are suppressed. This is
to simplify logins for non-human users, such as uucp(1). Login then records an entry in utmpx(5) and
the like, and executes the user's command interpreter (or the program specified on the command line if
-f is specified).
Login enters information into the environment (see environ(7)) specifying the user's home directory
(HOME), command interpreter (SHELL), search path (PATH), terminal type (TERM) and user name (both LOG-NAME LOGNAME
NAME and USER).
The standard shells, csh(1) and sh(1), do not fork before executing the login utility.
FILES
/etc/motd message-of-the-day
/etc/nologin disallows logins
/var/run/utmpx current logins
/var/mail/user system mailboxes
.hushlogin makes login quieter
SEE ALSO
chpass(1), passwd(1), rlogin(1), getpass(3), utmpx(5), environ(7)
HISTORY
A login appeared in Version 6 AT&T UNIX.
4th Berkeley Distribution May 5, 1994 4th Berkeley Distribution
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