LOGIN(1) BSD Reference Manual LOGIN(1)
login - log into the computer
login [-fp] [-h hostname] [user]
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
-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.
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
Login enters information into the environment (see environ(7)) specify-
ing 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
/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
chpass(1), passwd(1), rlogin(1), getpass(3), utmp(5), environ(7),
A login appeared in Version 6 AT&T UNIX.
4th Berkeley Distribution May 5, 1994 1