login(1) - NetBSD Manual Pages

LOGIN(1)                    NetBSD Reference Manual                   LOGIN(1)


NAME

     login - authenticate users and set up their session environment


SYNOPSIS

     login [-fps] [-h hostname] [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 done via passwords.  If the user can be authenticated via S/Key, then
     the S/Key challenge is incorporated in the password prompt.  The user
     then has the option of entering their Kerberos or normal password or the
     S/Key response.  Neither will be echoed.

     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.

     -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.

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

     -s      Require a secure authentication mechanism like Kerberos or S/Key
             to be used.

     If a user other than the superuser attempts to login while the file
     /etc/nologin exists, login displays its contents to the user and exits.
     This is used by shutdown(8) to prevent normal 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, 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 the wtmp(5) and utmp(5) files, executes site-specific login
     commands via the ttyaction(3) facilty with an action of "login", and exe-
     cutes 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.


FILES

     /etc/motd          message-of-the-day
     /etc/nologin       disallows non-superuser logins
     /var/run/utmp      list of current logins
     /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), kerberos(1), passwd(1), rlogin(1), skey(1), getpass(3),
     ttyaction(3), utmp(5), environ(7)


HISTORY

     A login appeared in Version 6 AT&T UNIX.


TRADEMARKS AND PATENTS

     S/Key is a trademark of Bellcore.

NetBSD 1.4                     January 13, 1999                              2