xref: /netbsd-src/share/man/man5/boot.cfg.5 (revision cd22f25e6f6d1cc1f197fe8c5468a80f51d1c4e1)
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28.Dd May 2, 2008
29.Dt BOOT.CFG 5
30.Os
31.Sh NAME
32.Nm boot.cfg
33.Nd configuration file for /boot
34.Sh DESCRIPTION
35The file /boot.cfg
36is used to alter the behaviour of the standard boot loader described in
37.Xr boot 8 .
38Configuration changes include setting the timeout, choosing a console device,
39altering the banner text and displaying a menu allowing boot commands to be
40easily chosen.
41If a
42.Nm
43file is not present, the system will boot as normal.
44.Ss FILE FORMAT
45The format of the file is a series of lines containing keyword/value pairs
46separated by an equals sign
47.Pq Sq = .
48There should be no whitespace surrounding the equals sign.
49Lines beginning with a hash
50.Pq Sq #
51are comments and will be ignored.
52.Pp
53Some keywords can be present multiple times in the file to define additional
54items.
55Such keywords are noted below.
56.Pp
57.Bl -tag -width timeout
58.It Sy banner
59(may be present multiple times)
60The text from banner lines is displayed instead of the standard welcome text
61by the boot loader.
62Up to 10 lines can be defined.
63No special character sequences are recognised, so to specify a blank line, a
64banner line with no value should be given.
65.It Sy menu
66(may be present multiple times)
67Used to define a menu item to be displayed to the end-user at boot time
68which allows a series of boot commands to be run without further typing.
69The value consists of the required menu text, followed by a colon
70.Pq Sq \&:
71and then the desired command.
72If the specified menu text is empty
73(the colon appears immediately after the equals sign),
74then the displayed menu text is the same as the command.
75For example:
76.Bd -literal
77menu=Boot normally:boot
78menu=Boot single-user:boot -s
79menu=:boot hd1a:netbsd -as
80.Ed
81.Pp
82Each menu item will be prefixed by an ascending number when displayed,
83i.e. the order in the
84.Nm
85file is important.
86.Pp
87The command is executed just as though the user had typed it in
88and so can be any valid command that would be accepted at the
89normal boot prompt.
90In addition,
91.So prompt Sc
92can be used to drop to the normal boot prompt.
93.It Sy timeout
94If the value is greater than zero, this specifies the time in seconds
95that the boot loader will wait for the end-user to choose a menu item.
96During the countdown period, they may press Return to choose the default
97option or press a number key corresponding to a menu option.
98If any other key is pressed, the countdown will stop and the user will be
99prompted to choose a menu option with no further time limit.
100If the timeout value is set to zero, the default option will be booted
101immediately.
102If the timeout value is negative or is not a number, there will be no
103time limit for the user to choose an option.
104.It Sy default
105Used to specify the default menu item  which will be chosen in the case of
106Return being pressed or the timeout timer reaching zero.
107The value is the number of the menu item as displayed.
108As described above, the menu items are counted from 1 in the order listed in
109.Nm .
110If not specified, the default value will be option 1, i.e. the first item.
111.It Sy consdev
112Changes the console device to that specified in the value.
113Valid values are any of those that could be specified at the normal boot
114prompt with the consdev command.
115.It Sy load
116Used to load kernel modules, which will be passed on to the kernel for
117initialization during early boot.
118The argument is the complete path and file name of the module to be loaded.
119May be used as many times as needed.
120.El
121.Sh EXAMPLES
122Here is an example
123.Nm
124file:
125.Bd -literal -offset indent
126banner=Welcome to NetBSD
127banner==================
128banner=
129banner=Please choose an option from the following menu:
130menu=Boot normally:boot
131menu=Boot single-user:boot -s
132menu=Boot from second disk:boot hd1a:
133menu=Go to command line (advanced users only):prompt
134timeout=-1
135default=1
136load=/ramdisk.kmod
137.Ed
138.Pp
139This will display:
140.Bd -literal -offset indent
141Welcome to NetBSD
142=================
143
144Please choose an option from the following menu:
145
146      1. Boot normally
147      2. Boot single-user
148      3. Boot from second disk
149      4. Go to command line (advanced users only)
150
151Option [1]:
152.Ed
153.Pp
154It will then wait for the user to type 1, 2, 3 or 4 followed by Return.
155Pressing Return by itself will run option 1.
156There will be no timeout.
157.Sh SEE ALSO
158.Xr boot 8
159.Sh BUGS
160Support for
161.Nm
162is currently for
163.Nx Ns /i386 and
164.Nx Ns /amd64 only.
165It is hoped that its use will be extended to other appropriate ports that
166use the
167.Xr boot 8
168interface.
169.Sh HISTORY
170The
171.Nm
172utility appeared in
173.Nx 5.0 .
174.Sh AUTHORS
175The
176.Nm
177extensions to
178.Xr boot 8
179were written by
180.An Stephen Borrill
181.Aq sborrill@NetBSD.org .
182