log into the computer
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
prompts for a user name.
Authentication of users is configurable via
Password authentication is the default.
The following options are available:
- 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.
- Specify the host from which the connection was received. It is used by
various daemons such as
This option may only be used by the super-user.
- By default,
login discards any previous
-p option disables
Login access can be controlled via
or the login class in
which provides allow and deny records based on time, tty and remote host name.
If the file /etc/fbtab
changes the protection and ownership
of certain devices specified in this file.
Immediately after logging a user in,
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
exists in the user's home
directory, all of these messages are suppressed. This is to simplify logins
for non-human users, such as
utility enters information into the
specifying the user's home directory (HOME), command interpreter (SHELL),
search path (PATH), terminal type (TERM) and user name (both LOGNAME and
USER). Other environment variables may be set due to entries in the login
class capabilities database, for the login class assigned in the user's system
passwd record. The login class also controls the maximum and current process
resource limits granted to a login, process priorities and many other aspects
of a user's login environment.
Some shells may provide a builtin
command which is similar or identical to this utility. Consult the
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
- changes device protections
- login class capabilities database
- system mailboxes
- makes login quieter
- user flags for auditing
- global flags for auditing
utility appeared in
Version 6 AT&T UNIX