10. Getty and Login
Getty is the program that enables you to log in through a serial device such as a virtual terminal, a text terminal, or a modem. It displays the login prompt. Once you enter your username, getty hands this over to login
which asks for a password, checks it out and gives you a shell.
There are many getty's available. Some distributions, including Red Hat use
a very small one called mingetty
that only works with virtual terminals.
The login
program is part of the util-linux package, which also
contains a getty called agetty
, which works fine. This package also
contains mkswap
, fdisk
,
passwd
, kill
, setterm
, mount
,
swapon
, rdev
, renice
,
more
(the program) and more (ie more programs).
10.1 Configuration
The message that comes on the top of your screen with your login prompt comes
from /etc/issue
. Gettys are usually started in /etc/inittab
.
Login checks user details in /etc/passwd
, and if you have password
shadowing, /etc/shadow
.
10.2 Exercises
Create a /etc/passwd
by hand. Passwords can be set to null, and
changed with the program passwd
once you log on. See the man page for
this file Use man 5 passwd
to get the man page for the file rather
than the man page for the program.
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