login.1

UNIX v6源代码 这几乎是最经典的unix版本 unix操作系统设计和莱昂氏unix源代码分析都是用的该版

.th LOGIN I 3/15/72
.sh NAME
login  \*-  sign onto UNIX
.sh SYNOPSIS
.bd login
[ username ]
.sh DESCRIPTION
The
.it login
command
is used when a user initially
signs onto UNIX, 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.
.s3
If
.it 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.
.s3
After a successful login,
accounting files are updated and
the user is informed of the
existence of
.it .mail
and message-of-the-day files.
.it Login
initializes the user and group IDs and the working directory,
then executes a command interpreter (usually
.it sh
(I)) according to specifications found in a password file.
.s3
Login is recognized by the Shell
and executed directly (without forking).
.sh FILES
/etc/utmp	accounting
.br
/usr/adm/wtmp	accounting
.br
.li
.mail		mail
.br
/etc/motd	message-of-the-day
.br
/etc/passwd	password file
.sh "SEE ALSO"
init (VIII), getty (VIII), mail (I), passwd (I), passwd (V)
.sh DIAGNOSTICS
`login incorrect,'
if the name or the password is bad.
`No Shell,', `cannot open password file,' `no directory':
consult a UNIX programming counselor.
.sh BUGS