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login(1) [suse man page]

LOGIN(1)						   Linux Administrator's Manual 						  LOGIN(1)

NAME
login - Begin session on the system SYNOPSIS
login [ -p ] [ -h host ] [ -H ] [ -f username | username ] DESCRIPTION
login is used when signing onto a system. If no argument is given, login prompts for the username. The user is then prompted for a password, where approprate. Echoing is disabled to prevent revealing the password. Only a small number of password failures are permitted before login exits and the communications link is severed. If password aging has been enabled for the account, the user may be prompted for a new password before proceeding. He will be forced to provide his old password and the new password before continuing. Please refer to passwd(1) for more information. The user and group ID will be set according to their values in the file. There is one exception if the user ID is zero: in this case, only the primary group ID of the account is set. This should prevent that the system adminitrator cannot login in case of network problems. The value for $HOME, $SHELL, $PATH, $LOGNAME, and $MAIL are set according to the appropriate fields in the password entry. $PATH defaults to /usr/local/bin:/bin:/usr/bin:. for normal users, and to /sbin:/bin:/usr/sbin:/usr/bin for root if not other configured. The environment variable $TERM will be preserved, if it exists (other environment variables are preserved if the -p option is given) or be initialize to the terminal type on your tty line, as specified in /etc/ttytype. Then the user's shell is 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). login reads the /etc/login.defs(5) configuration file. Please refer to this documenation for options which could be set. OPTIONS
-p Used by getty(8) to tell login not to destroy the environment -f Used to skip a second login authentication. This option is deprecated and should not be used. It does specifically not work for root. Using this option also means, that not all PAM functions are called. -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. -H Used by other servers (i.e., telnetd(8)) to tell login that printing the hostname should be suppressed in the login: prompt. FILES
/var/run/utmp - list of current login sessins /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/login.defs - configuration file SEE ALSO
init(8), getty(8), mail(1), passwd(1), passwd(5), environ(7), shutdown(8), login.defs(5) BUGS
A recursive login, as used to be possible in the good old days, no longer works; for most purposes su(1) is a satisfactory substitute. Indeed, for security reasons, login does a vhangup() system call to remove any possible listening processes on the tty. This is to avoid password sniffing. If one uses the command "login", then the surrounding shell gets killed by vhangup() because it's no longer the true owner of the tty. This can be avoided by using "exec login" in a top-level shell or xterm. 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) Added new features: Thorsten Kukuk (kukuk@suse.de) PAM Login 3.32 2. May 2007 LOGIN(1)

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LOGIN(1)						    BSD General Commands Manual 						  LOGIN(1)

NAME
login -- log into the computer SYNOPSIS
login [-fp] [-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. 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 option disables this behavior. 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, 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 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. FILES
/etc/motd message-of-the-day /etc/nologin disallows logins /var/run/utmp 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), passwd(1), rlogin(1), getpass(3), utmp(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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