login

LOGIN(1)                                                              LOGIN(1)



NAME
       login - begin session on the system

SYNOPSIS
       login [-p] [username] [ENV=VAR ...]
       login [-p] [-h host] [-f username]
       login [-p] -r host

DESCRIPTION
       login  is  used to establish a new session with the system.  It is nor-
       mally invoked automatically by responding to the login: prompt  on  the
       user's  terminal.   login  may  be  special to the shell and may not be
       invoked as a sub-process.  Typically, login is treated by the shell  as
       exec  login  which  causes  the  user  to  exit from the current shell.
       Attempting to execute login from any shell but  the  login  shell  will
       produce an error message.

       When  invoked  from the login: prompt, the user may enter environmental
       variables after the username.  These variables are entered in the  form
       NAME=VALUE.  Not all variables may be set in the fashion, notably PATH,
       HOME and SHELL.  Additionally, IFS may be inhibited if the user's login
       shell is /bin/sh.

       The  user  is then prompted for a password, where appropriate.  Echoing
       is disabled to prevent revealing the password.  Only a small number  of
       password  failures  are permitted before login exits and the communica-
       tions link is severed.

       If password aging has  been  enabled  for  your  account,  you  may  be
       prompted  for  a new password before proceeding.  You will be forced to
       provide your old password  and  the  new  password  before  continuing.
       Please refer to passwd(1) for more information.

       After  a  successful login, you will be informed of any system messages
       and the presence of mail.  You may turn off the printing of the  system
       message  file,  /etc/motd, by creating a zero-length file .hushlogin in
       your login directory.  The mail message will be one of  "You  have  new
       mail.",  "You  have mail.", or "No Mail." according to the condition of
       your mailbox.

       Your user and group ID will be set according to  their  values  in  the
       /etc/passwd  file.   The  value for $HOME, $SHELL, $PATH, $LOGNAME, and
       $MAIL are set according to  the  appropriate  fields  in  the  password
       entry.   Ulimit,  umask  and  nice  values may also be set according to
       entries in the GECOS field.

       On some installations, the environmental variable $TERM  will  be  ini-
       tialized  to  the  terminal  type  on  your  tty  line, as specified in
       /etc/ttytype.

       An initialization script for your command interpreter may also be  exe-
       cuted.   Please see the appropriate manual section for more information
       on this function.

       A subsystem login is indicated by the presense of a "*"  as  the  first
       character  of the login shell. The given home directory will be used as
       the root of a new filesystem which the user is actually logged into.

OPTIONS
       -p     Preserve environment.

       -f     Do not perform authentication, user is preauthenticated.

       -h     Name of the remote host for this login.

       -r     Perform autologin protocol for rlogin.

       The -r, -h and -f options are only used when login is invoked by  root.

CAVEATS
       This  version of login has many compilation options, only some of which
       may be in use at any particular site.

       The location of files is subject to differences  in  system  configura-
       tion.

       The  login  program is NOT responsible for removing users from the utmp
       file.  It is the responsibility of getty(8) and  init(8)  to  clean  up
       apparent  ownership  of  a terminal session.  If you use login from the
       shell prompt without exec, the user you use will continue to appear  to
       be logged in even after you log out of the "subsession".

FILES
       /var/run/utmp - list of current login sessions
       /var/log/wtmp - list of previous login sessions
       /etc/passwd - user account information
       /etc/shadow - encrypted passwords and age information
       /etc/motd - system message file
       /etc/nologin - prevent non-root users from logging in
       /etc/ttytype - list of terminal types
       $HOME/.profile - initialization script for default shell
       $HOME/.hushlogin - suppress printing of system messages

SEE ALSO
       mail(1), passwd(1), sh(1), su(1), login.defs(5), nologin(5), passwd(5),
       getty(8)

AUTHOR
       Julianne Frances Haugh <jockgrrl AT ix.com>



                                                                      LOGIN(1)