login(1) [bsd man page]
LOGIN(1) General Commands Manual LOGIN(1) NAME
login - sign on SYNOPSIS
login [ -p ] [ username ] DESCRIPTION
The login command is used when a user initially signs on, or it may be used at any time to change from one user to another. The latter case is the one summarized above and described here. See "How to Get Started" for how to dial up initially. If login is invoked without an argument, it asks for a user name, and, if appropriate, a password. Echoing is turned off (if possible) during the typing of the password, so it will not appear on the written record of the session. After a successful login, accounting files are updated and the user is informed of the existence of mail. The message of the day is printed, as is the time of his last login. Both are suppressed if he has a ".hushlogin" file in his home directory; this is mostly used to make life easier for non-human users, such as uucp. Login initializes the user and group IDs and the working directory, then executes a command interpreter (usually csh(1)) according to spec- ifications found in a password file. Argument 0 of the command interpreter is the name of the command interpreter with a leading dash ("-"). Login also modifies the environment environ(7) with information specifying home directory, command interpreter, terminal type (if avail- able) and user name. The `-p' argument causes the remainder of the environment to be preserved, otherwise any previous environment is dis- carded. If the file /etc/nologin exists, login prints its contents on the user's terminal and exits. This is used by shutdown(8) to stop users log- ging in when the system is about to go down. Login is recognized by sh(1) and csh(1) and executed directly (without forking). FILES
/var/run/utmp accounting /usr/adm/wtmp accounting /usr/spool/mail/* mail /etc/motd message-of-the-day /etc/passwd password file /etc/nologin stops logins .hushlogin makes login quieter SEE ALSO
init(8), getty(8), mail(1), passwd(1), passwd(5), environ(7), shutdown(8), rlogin(1c) DIAGNOSTICS
"Login incorrect," if the name or the password is bad. "No Shell", "cannot open password file", "no directory": consult a programming counselor. BUGS
An undocumented option, -r is used by the remote login server, rlogind(8C) to force login to enter into an initial connection protocol. -h is used by telnetd(8C) and other servers to list the host from which the connection was received. 4th Berkeley Distribution November 27, 1996 LOGIN(1)
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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 configurable via pam(8). Password authentication is the default. The following options are available: -f When a user name is specified, this option indicates 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 argu- ments follows the user name. -h Specify 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 direc- tory. 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, all of these messages are suppressed. -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 speci- fied). The login utility 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). Some shells may provide a builtin login command which is similar or identical to this utility. Consult the builtin(1) manual page. The login utility will submit an audit record when login succeeds or fails. Failure to determine the current auditing state will result in an error exit from login. 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 /etc/pam.d/login pam(8) configuration file /etc/security/audit_user user flags for auditing /etc/security/audit_control global flags for auditing SEE ALSO
builtin(1), chpass(1), newgrp(1), passwd(1), rlogin(1), getpass(3), utmpx(5), environ(7) HISTORY
A login utility appeared in Version 6 AT&T UNIX. BSD
September 13, 2006 BSD