xref: /netbsd-src/share/man/man5/boot.cfg.5 (revision b5677b36047b601b9addaaa494a58ceae82c2a6c)
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28.Dd December 13, 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
36.Pa /boot.cfg
37is used to alter the behaviour of the standard boot loader described in
38.Xr boot 8 .
39Configuration changes include setting the timeout, choosing a console device,
40altering the banner text and displaying a menu allowing boot commands to be
41easily chosen.
42If a
43.Nm
44file is not present, the system will boot as normal.
45.Ss FILE FORMAT
46The format of the file is a series of lines containing keyword/value pairs
47separated by an equals sign
48.Pq Sq = .
49There should be no whitespace surrounding the equals sign.
50Lines beginning with a hash
51.Pq Sq #
52are comments and will be ignored.
53.Pp
54Some keywords can be present multiple times in the file to define additional
55items.
56Such keywords are noted below.
57.Pp
58.Bl -tag -width timeout
59.It Sy banner
60(may be present multiple times)
61The text from banner lines is displayed instead of the standard welcome text
62by the boot loader.
63Up to 10 lines can be defined.
64No special character sequences are recognised, so to specify a blank line, a
65banner line with no value should be given.
66.It Sy clear
67If nonzero, clear the screen before printing the banner.
68If zero, do not clear the screen (the default).
69.It Sy consdev
70Changes the console device to that specified in the value.
71Valid values are any of those that could be specified at the normal boot
72prompt with the consdev command.
73.It Sy default
74Used to specify the default menu item  which will be chosen in the case of
75Return being pressed or the timeout timer reaching zero.
76The value is the number of the menu item as displayed.
77As described above, the menu items are counted from 1 in the order listed in
78.Nm .
79If not specified, the default value will be option 1, i.e. the first item.
80.It Sy format
81Changes how the menu options are displayed.
82Should be set to one of
83.Sq a
84for automatic,
85.Sq l
86for letters and
87.Sq n
88for numbers.
89If set to automatic (the default), menu options will be displayed numerically
90unless there are more than 9 options and the timeout is greater than zero.
91If there are more than 9 options with a timeout greater than zero and
92the format is set to number, only the first 9 options will be available.
93.It Sy load
94Used to load kernel modules, which will be passed on to the kernel for
95initialization during early boot.
96The argument is the complete path and file name of the module to be loaded.
97May be used as many times as needed.
98.It Sy menu
99(may be present multiple times)
100Used to define a menu item to be displayed to the end-user at boot time
101which allows a series of boot commands to be run without further typing.
102The value consists of the required menu text, followed by a colon
103.Pq Sq \&:
104and then the desired command(s).
105Multiple commands can be specified separated by a semi-colon.
106If the specified menu text is empty
107(the colon appears immediately after the equals sign),
108then the displayed menu text is the same as the command.
109For example:
110.Bd -literal
111menu=Boot normally:boot
112menu=Boot single-user:boot -s
113menu=Boot with module foo:load /foo.kmod;boot
114menu=Boot with serial console:consdev com0;boot
115menu=:boot hd1a:netbsd -as
116.Ed
117.Pp
118Each menu item will be prefixed by an ascending number when displayed,
119i.e. the order in the
120.Nm
121file is important.
122.Pp
123Each command is executed just as though the user had typed it in
124and so can be any valid command that would be accepted at the
125normal boot prompt.
126In addition,
127.Dq Ic prompt
128can be used to drop to the normal boot prompt.
129.It Sy timeout
130If the value is greater than zero, this specifies the time in seconds
131that the boot loader will wait for the end-user to choose a menu item.
132During the countdown period, they may press Return to choose the default
133option or press a number key corresponding to a menu option.
134If any other key is pressed, the countdown will stop and the user will be
135prompted to choose a menu option with no further time limit.
136If the timeout value is set to zero, the default option will be booted
137immediately.
138If the timeout value is negative or is not a number, there will be no
139time limit for the user to choose an option.
140.El
141.Sh EXAMPLES
142Here is an example
143.Nm
144file:
145.Bd -literal -offset indent
146banner=Welcome to NetBSD
147banner==================
148banner=
149banner=Please choose an option from the following menu:
150menu=Boot normally:boot
151menu=Boot single-user:boot -s
152menu=Boot from second disk:boot hd1a:
153menu=Boot with module foo:load /foo.kmod;boot
154menu=Boot with modules foo and bar:load /foo.kmod;load /bar.kmod;boot
155menu=Boot Xen with 256MB for dom0:load /netbsd-XEN3_DOM0 console=pc;multiboot /usr/pkg/xen3-kernel/xen.gz dom0_mem=256M
156menu=Boot Xen with 256MB for dom0 (serial):load /netbsd-XEN3_DOM0 console=com0;multiboot /usr/pkg/xen3-kernel/xen.gz dom0_mem=256M console=com1 com1=115200,8n1
157menu=Boot Xen with dom0 in single-user mode:load /netbsd-XEN3_DOM0 -s;multiboot /usr/pkg/xen3-kernel/xen.gz dom0_mem=256M
158menu=Go to command line (advanced users only):prompt
159clear=1
160timeout=-1
161default=1
162# Always load ramdisk module
163load=/miniroot.kmod
164.Ed
165.Pp
166N.B. Xen counts serial ports from com1 upwards, but
167.Nx
168counts from com0, so the appropriate device name must be used.
169Please see the Xen with serial console example above.
170.Pp
171This will clear the screen and display:
172.Bd -literal -offset indent
173Welcome to NetBSD
174=================
175
176Please choose an option from the following menu:
177
178      1. Boot normally
179      2. Boot single-user
180      3. Boot from second disk
181      4. Boot with module foo
182      5. Boot with modules foo and bar
183      6. Boot Xen with 256 MB for dom0
184      7. Boot Xen with 256 MB for dom0 (serial)
185      8. Boot Xen with dom0 in single-user mode
186      9. Go to command line (advanced users only)
187
188Option [1]:
189.Ed
190.Pp
191It will then wait for the user to type 1, 2, 3, 4, 5, 6, 7, 8 or 9 followed by
192Return.
193Pressing Return by itself will run option 1.
194There will be no timeout.
195.Sh SEE ALSO
196.Xr boot 8
197.Sh HISTORY
198The
199.Nm
200utility appeared in
201.Nx 5.0 .
202.Sh AUTHORS
203The
204.Nm
205extensions to
206.Xr boot 8
207were written by
208.An Stephen Borrill
209.Aq sborrill@NetBSD.org .
210.Sh BUGS
211Support for
212.Nm
213is currently for
214.Nx Ns /i386
215and
216.Nx Ns /amd64
217only.
218It is hoped that its use will be extended to other appropriate ports that
219use the
220.Xr boot 8
221interface.
222