NAME

login − login to a UNIX system

SYNTAX

login [ 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 and message-of-the-day files.  The login command initializes the user and group IDs and the working directory, and sets the HOME, PATH, TERM, SHELL and USER environment variables. It then executes a command interpreter, usually sh(1) or csh(1), according to specifications found in a password file.  If the command interpreter is /bin/csh, the new line discipline is entered, otherwise the terminal stop characters are set to be undefined.  For further information see stty(1).  Argument 0 of the command interpreter starts with a ’−’. 

Login is recognized by sh(1) and csh(1) and executed directly (without forking). 

DIAGNOSTICS

“Login incorrect,” if the name or the password is bad. 
“No Shell”, “cannot open password file”, “no directory”: consult a programming counselor.

FILES

/etc/utmpaccounting
/usr/adm/wtmpaccounting
/usr/spool/mail/*mail
/etc/motdmessage-of-the-day
/etc/passwdpassword file
/etc/profileSystem profile (/bin/sh)
/etc/cshprofileSystem profile (/bin/csh)
$HOME/.profileUser’s login profile (/bin/sh)
$HOME/.loginUser’s login profile (/bin/csh)

SEE ALSO

mail(1), newgrp(1), passwd(1), passwd(5), profile(5), getty(8), init(8)