Unless FreeBSD has been configured to automatically start a graphical environment during startup, the system will boot into a command line login prompt, as seen in this example:
FreeBSD/amd64 (pc3.example.org) (ttyv0) login:
The first line contains some information about the system.
The amd64 indicates that the system in this
example is running a 64-bit version of FreeBSD. The hostname is
pc3.example.org, and
ttyv0 indicates that this is the
“system console”. The second line is the login
prompt.
Since FreeBSD is a multiuser system, it needs some way to distinguish between different users. This is accomplished by requiring every user to log into the system before gaining access to the programs on the system. Every user has a unique name “username” and a personal “password”.
To log into the system console, type the username that was configured during system installation, as described in Section 2.8.6, “Add Users”, and press Enter. Then enter the password associated with the username and press Enter. The password is not echoed for security reasons.
Once the correct password is input, the message of the
day (MOTD) will be displayed followed
by a command prompt. Depending upon the shell that was
selected when the user was created, this prompt will be a
#, $, or
% character. The prompt indicates that
the user is now logged into the FreeBSD system console and ready
to try the available commands.
While the system console can be used to interact with the system, a user working from the command line at the keyboard of a FreeBSD system will typically instead log into a virtual console. This is because system messages are configured by default to display on the system console. These messages will appear over the command or file that the user is working on, making it difficult to concentrate on the work at hand.
By default, FreeBSD is configured to provide several virtual consoles for inputting commands. Each virtual console has its own login prompt and shell and it is easy to switch between virtual consoles. This essentially provides the command line equivalent of having several windows open at the same time in a graphical environment.
The key combinations
Alt+F1
through
Alt+F8
have been reserved by FreeBSD for switching between virtual
consoles. Use
Alt+F1
to switch to the system console
(ttyv0),
Alt+F2
to access the first virtual console
(ttyv1),
Alt+F3
to access the second virtual console
(ttyv2), and so on.
When switching from one console to the next, FreeBSD manages the screen output. The result is an illusion of having multiple virtual screens and keyboards that can be used to type commands for FreeBSD to run. The programs that are launched in one virtual console do not stop running when the user switches to a different virtual console.
Refer to syscons(4), atkbd(4), vidcontrol(1) and kbdcontrol(1) for a more technical description of the FreeBSD console and its keyboard drivers.
In FreeBSD, the number of available virtual consoles is
configured in this section of
/etc/ttys:
# name getty type status comments # ttyv0 "/usr/libexec/getty Pc" xterm on secure # Virtual terminals ttyv1 "/usr/libexec/getty Pc" xterm on secure ttyv2 "/usr/libexec/getty Pc" xterm on secure ttyv3 "/usr/libexec/getty Pc" xterm on secure ttyv4 "/usr/libexec/getty Pc" xterm on secure ttyv5 "/usr/libexec/getty Pc" xterm on secure ttyv6 "/usr/libexec/getty Pc" xterm on secure ttyv7 "/usr/libexec/getty Pc" xterm on secure ttyv8 "/usr/X11R6/bin/xdm -nodaemon" xterm off secure
To disable a virtual console, put a comment symbol
(#) at the beginning of the line
representing that virtual console. For example, to reduce the
number of available virtual consoles from eight to four, put a
# in front of the last four lines
representing virtual consoles ttyv5
through ttyv8.
Do not comment out the line for the
system console ttyv0. Note that the last
virtual console (ttyv8) is used to access
the graphical environment if Xorg
has been installed and configured as described in
Chapter 6, The X Window System.
For a detailed description of every column in this file and the available options for the virtual consoles, refer to ttys(5).
The FreeBSD boot menu provides an option labelled as
“Boot Single User”. If this option is selected,
the system will boot into a special mode known as
“single user mode”. This mode is typically used
to repair a system that will not boot or to reset the
root password when
it is not known. While in single user mode, networking and
other virtual consoles are not available. However, full
root access to the
system is available, and by default, the
root password is not
needed. For these reasons, physical access to the keyboard is
needed to boot into this mode and determining who has physical
access to the keyboard is something to consider when securing
a FreeBSD system.
The settings which control single user mode are found in
this section of /etc/ttys:
# name getty type status comments # # If console is marked "insecure", then init will ask for the root password # when going to single-user mode. console none unknown off secure
By default, the status is set to
secure. This assumes that who has physical
access to the keyboard is either not important or it is
controlled by a physical security policy. If this setting is
changed to insecure, the assumption is that
the environment itself is insecure because anyone can access
the keyboard. When this line is changed to
insecure, FreeBSD will prompt for the
root password when a
user selects to boot into single user mode.
Be careful when changing this setting to
insecure! If the
root password is
forgotten, booting into single user mode is still possible,
but may be difficult for someone who is not familiar with
the FreeBSD booting process.
The FreeBSD console default video mode may be adjusted to
1024x768, 1280x1024, or any other size supported by the
graphics chip and monitor. To use a different video mode
load the VESA module:
#kldload vesa
To determine which video modes are supported by the hardware, use vidcontrol(1). To get a list of supported video modes issue the following:
#vidcontrol -i mode
The output of this command lists the video modes that are
supported by the hardware. To select a new video mode,
specify the mode using vidcontrol(1) as the
root user:
#vidcontrol MODE_279
If the new video mode is acceptable, it can be permanently
set on boot by adding it to
/etc/rc.conf:
allscreens_flags="MODE_279"
All FreeBSD documents are available for download at http://ftp.FreeBSD.org/pub/FreeBSD/doc/
Questions that are not answered by the
documentation may be
sent to <[email protected]>.
Send questions about this document to <[email protected]>.