login(1) User Commands login(1)
login - sign on to the system
login [-p] [-d device] [-R repository] [-s service]
[-t terminal] [-u identity] [-U ruser]
[-h hostname [terminal] | -r hostname]
The login command is used at the beginning of each terminal session to identify oneself to the system. login is invoked by the system when
a connection is first established, after the previous user has terminated the login shell by issuing the exit command.
If login is invoked as a command, it must replace the initial command interpreter. To invoke login in this fashion, type:
from the initial shell. The C shell and Korn shell have their own built-ins of login. See ksh(1), ksh93(1), and csh(1) for descriptions of
login built-ins and usage.
login asks for your user name, if it is not supplied as an argument, and your password, if appropriate. Where possible, echoing is turned
off while you type your password, so it does not appear on the written record of the session.
If you make any mistake in the login procedure, the message:
is printed and a new login prompt appears. If you make five incorrect login attempts, all five can be logged in /var/adm/loginlog, if it
exists. The TTY line is dropped.
If password aging is turned on and the password has aged (see passwd(1) for more information), the user is forced to changed the password.
In this case the /etc/nsswitch.conf file is consulted to determine password repositories (see nsswitch.conf(4)). The password update con-
figurations supported are limited to the following five cases.
o passwd: files
o passwd: files nis
o passwd: files nisplus
o passwd: compat (==> files nis)
o passwd: compat (==> files nisplus)
Failure to comply with the configurations prevents the user from logging onto the system because passwd(1) fails. If you do not complete
the login successfully within a certain period of time, it is likely that you are silently disconnected.
After a successful login, accounting files are updated. Device owner, group, and permissions are set according to the contents of the
/etc/logindevperm file, and the time you last logged in is printed (see logindevperm(4)).
The user-ID, group-ID, supplementary group list, and working directory are initialized, and the command interpreter (usually ksh) is
The basic environment is initialized to:
For Bourne shell and Korn shell logins, the shell executes /etc/profile and $HOME/.profile, if it exists.
For the ksh93 Korn shell, an interactive shell then executes /etc/ksh.kshrc, followed by the file specified by the ENV environment vari-
able. If $ENV is not set, this defaults to $HOME/.kshrc. For the ksh and /usr/xpg4/bin/sh Korn Shell, an interactive shell executes the
file named by $ENV (no default).
For C shell logins, the shell executes /etc/.login, $HOME/.cshrc, and $HOME/.login. The default /etc/profile and /etc/.login files check
quotas (see quota(1M)), print /etc/motd, and check for mail. None of the messages are printed if the file $HOME/.hushlogin exists. The name
of the command interpreter is set to - (dash), followed by the last component of the interpreter's path name, for example, -sh.
If the login-shell field in the password file (see passwd(4)) is empty, then the default command interpreter, /usr/bin/sh, is used. If this
field is * (asterisk), then the named directory becomes the root directory. At that point, login is re-executed at the new level, which
must have its own root structure.
The environment can be expanded or modified by supplying additional arguments to login, either at execution time or when login requests
your login name. The arguments can take either the form xxx or xxx=yyy. Arguments without an = (equal sign) are placed in the environment
where n is a number starting at 0 and is incremented each time a new variable name is required. Variables containing an = (equal sign) are
placed in the environment without modification. If they already appear in the environment, then they replace the older values.
There are two exceptions: The variables PATH and SHELL cannot be changed. This prevents people logged into restricted shell environments
from spawning secondary shells that are not restricted. login understands simple single-character quoting conventions. Typing a (back-
slash) in front of a character quotes it and allows the inclusion of such characters as spaces and tabs.
Alternatively, you can pass the current environment by supplying the -p flag to login. This flag indicates that all currently defined envi-
ronment variables should be passed, if possible, to the new environment. This option does not bypass any environment variable restrictions
mentioned above. Environment variables specified on the login line take precedence, if a variable is passed by both methods.
To enable remote logins by root, edit the /etc/default/login file by inserting a # (pound sign) before the CONSOLE=/dev/console entry. See
For accounts in name services which support automatic account locking, the account can be configured to be automatically locked (see
user_attr(4) and policy.conf(4)) if successive failed login attempts equals or exceeds RETRIES. Currently, only the files repository (see
passwd(4) and shadow(4)) supports automatic account locking. See also pam_unix_auth(5).
The login command uses pam(3PAM) for authentication, account management, session management, and password management. The PAM configuration
policy, listed through /etc/pam.conf, specifies the modules to be used for login. Here is a partial pam.conf file with entries for the
login command using the UNIX authentication, account management, and session management modules:
login auth required pam_authtok_get.so.1
login auth required pam_dhkeys.so.1
login auth required pam_unix_auth.so.1
login auth required pam_dial_auth.so.1
login account requisite pam_roles.so.1
login account required pam_unix_account.so.1
login session required pam_unix_session.so.1
The Password Management stack looks like the following:
other password required pam_dhkeys.so.1
other password requisite pam_authtok_get.so.1
other password requisite pam_authtok_check.so.1
other password required pam_authtok_store.so.1
If there are no entries for the service, then the entries for the other service is used. If multiple authentication modules are listed,
then the user can be prompted for multiple passwords.
When login is invoked through rlogind or telnetd, the service name used by PAM is rlogin or telnet, respectively.
The following options are supported:
-d device login accepts a device option, device. device is taken to be the path name of the TTY port login is to operate
on. The use of the device option can be expected to improve login performance, since login does not need to call
ttyname(3C). The -d option is available only to users whose UID and effective UID are root. Any other attempt to
use -d causes login to quietly exit.
-h hostname [terminal] Used by in.telnetd(1M) to pass information about the remote host and terminal type.
Terminal type as a second argument to the -h option should not start with a hyphen (-).
-p Used to pass environment variables to the login shell.
-r hostname Used by in.rlogind(1M) to pass information about the remote host.
-R repository Used to specify the PAM repository that should be used to tell PAM about the "identity" (see option -u below). If
no "identity" information is passed, the repository is not used.
-s service Indicates the PAM service name that should be used. Normally, this argument is not necessary and is used only for
specifying alternative PAM service names. For example: "ktelnet" for the Kerberized telnet process.
-u identity Specifies the "identity" string associated with the user who is being authenticated. This usually is not be the
same as that user's Unix login name. For Kerberized login sessions, this is the Kerberos principal name associ-
ated with the user.
-U ruser Indicates the name of the person attempting to login on the remote side of the rlogin connection. When
in.rlogind(1M) is operating in Kerberized mode, that daemon processes the terminal and remote user name informa-
tion prior to invoking login, so the "ruser" data is indicated using this command line parameter. Normally (non-
Kerberos authenticated rlogin), the login daemon reads the remote user information from the client.
The following exit values are returned:
0 Successful operation.
$HOME/.cshrc Initial commands for each csh.
$HOME/.hushlogin Suppresses login messages.
$HOME/.kshrc User's commands for interactive ksh93, if $ENV is unset; executes after /etc/ksh.kshrc.
$HOME/.login User's login commands for csh.
$HOME/.profile User's login commands for sh, ksh, and ksh93.
$HOME/.rhosts Private list of trusted hostname/username combinations.
/etc/.login System-wide csh login commands.
/etc/issue Issue or project identification.
/etc/ksh.kshrc System-wide commands for interactive ksh93.
/etc/logindevperm Login-based device permissions.
/etc/nologin Message displayed to users attempting to login during machine shutdown.
/etc/passwd Password file.
/etc/profile System-wide sh, ksh, and ksh93 login commands.
/etc/shadow List of users' encrypted passwords.
/usr/bin/sh User's default command interpreter.
/var/adm/lastlog Time of last login.
/var/adm/loginlog Record of failed login attempts.
/var/mail/your-name Mailbox for user your-name.
/etc/default/login Default value can be set for the following flags in /etc/default/login. Default values are specified as comments in
the /etc/default/login file, for example, TIMEZONE=EST5EDT.
TIMEZONE Sets the TZ environment variable of the shell (see environ(5)).
HZ Sets the HZ environment variable of the shell.
ULIMIT Sets the file size limit for the login. Units are disk blocks. Default is zero (no limit).
CONSOLE If set, root can login on that device only. This does not prevent execution of remote com-
mands with rsh(1). Comment out this line to allow login by root.
PASSREQ Determines if login requires a non-null password.
ALTSHELL Determines if login should set the SHELL environment variable.
PATH Sets the initial shell PATH variable.
SUPATH Sets the initial shell PATH variable for root.
TIMEOUT Sets the number of seconds (between 0 and 900) to wait before abandoning a login session.
UMASK Sets the initial shell file creation mode mask. See umask(1).
SYSLOG Determines whether the syslog(3C) LOG_AUTH facility should be used to log all root logins at
level LOG_NOTICE and multiple failed login attempts atLOG_CRIT.
DISABLETIME If present, and greater than zero, the number of seconds that login waits after RETRIES
failed attempts or the PAM framework returns PAM_ABORT. Default is 20 seconds. Minimum is 0
seconds. No maximum is imposed.
SLEEPTIME If present, sets the number of seconds to wait before the login failure message is printed
to the screen. This is for any login failure other than PAM_ABORT. Another login attempt is
allowed, providing RETRIES has not been reached or the PAM framework is returned PAM_MAX-
TRIES. Default is 4 seconds. Minimum is 0 seconds. Maximum is 5 seconds.
Both su(1M) and sulogin(1M) are affected by the value of SLEEPTIME.
RETRIES Sets the number of retries for logging in (see pam(3PAM)). The default is 5. The maximum
number of retries is 15. For accounts configured with automatic locking (see SECURITY
above), the account is locked and login exits. If automatic locking has not been configured,
login exits without locking the account.
SYSLOG_FAILED_LOGINS Used to determine how many failed login attempts are allowed by the system before a failed
login message is logged, using the syslog(3C) LOG_NOTICE facility. For example, if the vari-
able is set to 0, login logs all failed login attempts.
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|Availability |SUNWcsu |
|Interface Stability |Committed |
csh(1), exit(1), ksh(1), ksh93(1), mail(1), mailx(1), newgrp(1), passwd(1), rlogin(1), rsh(1), sh(1), shell_builtins(1), telnet(1),
umask(1), in.rlogind(1M), in.telnetd(1M), logins(1M), quota(1M), su(1M), sulogin(1M), syslogd(1M), useradd(1M), userdel(1M), pam(3PAM),
rcmd(3SOCKET), syslog(3C), ttyname(3C), auth_attr(4), exec_attr(4), hosts.equiv(4), issue(4), logindevperm(4), loginlog(4), nologin(4),
nsswitch.conf(4), pam.conf(4), passwd(4), policy.conf(4), profile(4), shadow(4), user_attr(4), utmpx(4), wtmpx(4), attributes(5), envi-
ron(5), pam_unix_account(5), pam_unix_auth(5), pam_unix_session(5), pam_authtok_check(5), pam_authtok_get(5), pam_authtok_store(5),
pam_dhkeys(5), pam_passwd_auth(5), termio(7I)
The user name or the password cannot be matched.
Not on system console
Root login denied. Check the CONSOLE setting in /etc/default/login.
No directory! Logging in with home=/
The user's home directory named in the passwd(4) database cannot be found or has the wrong permissions. Contact your system administra-
Cannot execute the shell named in the passwd(4) database. Contact your system administrator.
NO LOGINS: System going down in N minutes
The machine is in the process of being shut down and logins have been disabled.
Users with a UID greater than 76695844 are not subject to password aging, and the system does not record their last login time.
If you use the CONSOLE setting to disable root logins, you should arrange that remote command execution by root is also disabled. See
rsh(1), rcmd(3SOCKET), and hosts.equiv(4) for further details.
The pam_unix(5) module is no longer supported. Similar functionality is provided by pam_unix_account(5), pam_unix_auth(5), pam_unix_ses-
sion(5), pam_authtok_check(5), pam_authtok_get(5), pam_authtok_store(5), pam_dhkeys(5), and pam_passwd_auth(5).
SunOS 5.11 7 Jan 2008 login(1)