MirOS Manual: login(1)

LOGIN(1)                     BSD Reference Manual                     LOGIN(1)

NAME

     login - log into the computer

SYNOPSIS

     login [-fp] [-h hostname] [-L local-ip-address] [-R remote-ip-address]
           [-u username] [user]

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
     normally done via passwords, though external authentication mechanisms
     may be used (see login.conf(5)). To specify the alternate authentication
     mechanism style, the string :style is appended to the user name (i.e.,
     user:style).

     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
             superuser or when an already logged in user is logging in as
             themselves.

     -h hostname
             Specifies the host from which the connection was received. This
             option may only be used by the superuser.

     -L      The -L option specifies the local IP address of a socket. This
             information is passed on to any classify script (see
             login.conf(5)).

     -p      By default, login discards any previous environment. The -p op-
             tion disables this behavior.

     -R      The -R option specifies the remote IP address of a socket. This
             information is passed on to any classify script (see
             login.conf(5)).

     -u username
             Specifies the remote user that initiated the connection. This op-
             tion may only be used by the superuser.

     If the file /etc/nologin exists (and the "ignorenologin" boolean is not
     set in the user's login class), login displays 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.

     If the file /etc/fbtab exists, login changes the protection and ownership
     of certain devices specified in this file.

     If the file /var/log/failedlogin exists, login will record failed login
     attempts in this file.

     Immediately after logging a user in, login displays the system copyright
     notice, the date and time the user last logged in, the date and time of
     the last unsuccessful login (if the file /var/log/failedlogin exists),
     the message of the day as well as other information. If the file
     ".hushlogin" exists in the user's home directory, all of these messages
     are suppressed. This is to simplify logins for non-human users, such as
     uucp. login then records an entry in the wtmp(5) and utmp(5) files and
     executes the user's command interpreter.

     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 LOGNAME and USER).

     The standard shells, csh(1) and sh(1), do not fork before executing the
     login utility.

     Note that if login is invoked by a non-root user, it will execute su(1)
     in login emulation mode instead.

ENVIRONMENT

     login sets the following environment variables:

     HOME        The user's home directory, as specified by the password data-
                 base.

     SHELL       The user's shell, as specified by the password database.

     TERM        The user's terminal type, if it can be determined.

     LOGNAME     The user's login name.

     USER        Same as LOGNAME.

     REMOTEHOST  The name of the host from which the user logged in, if the -h
                 flag was specified.

     REMOTEUSER  The name of the remote user who initiated the connection, if
                 the -u flag was specified.

     Other environment variables may be specified in /etc/login.conf via the
     "setenv" capability.

FILES

     /etc/fbtab            changes device protections
     /etc/login.conf       login configuration
     /etc/motd             message-of-the-day
     /etc/nologin          disallows logins
     /var/run/utmp         current logins
     /var/log/failedlogin  failed login account records
     /var/log/lastlog      last login account records
     /var/log/wtmp         login account records
     /var/mail/user        system mailboxes
     .hushlogin            makes login quieter

SEE ALSO

     chpass(1), passwd(1), su(1), telnet(1), getpass(3), setusercontext(3),
     fbtab(5), login.conf(5), utmp(5), environ(7)

HISTORY

     A login utility appeared in Version 3 AT&T UNIX.

MirOS BSD #10-current            May 5, 1994                                 1

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