Passwords can be found (in hashed form) in /etc/shadow and the users in /etc/passwd.
The login program is used to establish a new session with the system.
It is normally invoked automatically by responding to the login: prompt
on the user´s terminal. login may be special to the shell and may not
be invoked as a sub-process. Typically, login is treated by the shell
as exec login which causes the user to exit from the current shell.
Attempting to execute login from any shell but the login shell will
produce an error message.
The user is then prompted for a password, where appropriate. 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 your account, you may be
prompted for a new password before proceeding. You will be forced to
provide your old password and the new password before continuing.
Please refer to passwd(1) for more information.
Passwords can be found (in hashed form) in /etc/shadow and the users in /etc/passwd.
The login program is used to establish a new session with the system. It is normally invoked automatically by responding to the login: prompt on the user´s terminal. login may be special to the shell and may not be invoked as a sub-process. Typically, login is treated by the shell as exec login which causes the user to exit from the current shell. Attempting to execute login from any shell but the login shell will produce an error message.
More info at: http://manpages.ubuntu.com/manpages/hardy/man1/login.1.html
http://manpages.ubuntu.com/manpages/hardy/man5/passwd.5.html