kernel - Introduce lightweight buffers
[dragonfly.git] / sys / boot / common / help.common
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1################################################################################
2# Thelp DDisplay command help
3
4 help [topic [subtopic]]
bc65ccee 5 help index
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6 ?
7
8 The help command displays help on commands and their usage.
9
10 In command help, a term enclosed with <...> indicates a value as
11 described by the term. A term enclosed with [...] is optional,
12 and may not be required by all forms of the command.
13
14 Some commands may not be available. Use the '?' command to list
15 most available commands.
16
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17 If needed, disable the use of ACPI with:
18
19 unset acpi_load
bc65ccee 20 set hint.acpi.0.disabled="1"
5ee58eed 21
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22################################################################################
23# Tautoboot DBoot after a delay
24
25 autoboot [<delay> [<prompt>]]
26
27 Displays <prompt> or a default prompt, and counts down <delay> seconds
28 before attempting to boot. If <delay> is not specified, the default
29 value is 10.
30
31################################################################################
32# Tboot DBoot immediately
33
34 boot [<kernelname>] [-<arg> ...]
35
36 Boot the system. If arguments are specified, they are added to the
37 arguments for the kernel. If <kernelname> is specified, and a kernel
38 has not already been loaded, it will be booted instead of the default
39 kernel.
40
41################################################################################
42# Techo DEcho arguments
43
44 echo [-n] [<message>]
45
46 Emits <message>, with no trailing newline if -n is specified. This is
47 most useful in conjunction with scripts and the '@' line prefix.
48
49 Variables are substituted by prefixing them with $, eg.
50
51 echo Current device is $currdev
52
53 will print the current device.
54
55################################################################################
56# Tload DLoad a kernel or module
57
58 load [-t <type>] <filename>
59
60 Loads the module contained in <filename> into memory. If no other
61 modules are loaded, <filename> must be a kernel or the command will
62 fail.
63
64 If -t is specified, the module is loaded as raw data of <type>, for
65 later use by the kernel or other modules. <type> may be any string.
66
67################################################################################
68# Tls DList files
69
70 ls [-l] [<path>]
71
72 Displays a listing of files in the directory <path>, or the root
73 directory of the current device if <path> is not specified.
74
75 The -l argument displays file sizes as well; the process of obtaining
76 file sizes on some media may be very slow.
77
78################################################################################
79# Tlsdev DList devices
80
81 lsdev [-v]
82
83 List all of the devices from which it may be possible to load modules.
84 If -v is specified, print more details.
85
86################################################################################
87# Tlsmod DList modules
88
89 lsmod [-v]
90
91 List loaded modules. If [-v] is specified, print more details.
92
93################################################################################
94# Tmore DPage files
95
96 more <filename> [<filename> ...]
97
98 Show contents of text files. When displaying the contents of more,
99 than one file, if the user elects to quit displaying a file, the
100 remaining files will not be shown.
101
102################################################################################
103# Tpnpscan DScan for PnP devices
104
105 pnpscan [-v]
106
107 Scan for Plug-and-Play devices. This command is normally automatically
108 run as part of the boot process, in order to dynamically load modules
109 required for system operation.
110
111 If the -v argument is specified, details on the devices found will
112 be printed.
113
114################################################################################
115# Tset DSet a variable
116
117 set <variable name>
118 set <variable name>=<value>
119
120 The set command is used to set variables.
121
122################################################################################
123# Tset Sautoboot_delay DSet the default autoboot delay
124
125 set autoboot_delay=<value>
126
127 Sets the default delay for the autoboot command to <value> seconds.
128
129################################################################################
130# Tset Sbootfile DSet the default boot file set
131
132 set bootfile=<filename>[;<filename>...]
133
134 Sets the default set of kernel boot filename(s). It may be overridden
135 by setting the bootfile variable to a semicolon-separated list of
136 filenames, each of which will be searched for in the module_path
5ee58eed 137 directories. The default bootfile set is "kernel".
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138
139################################################################################
140# Tset Sboot_askname DPrompt for root device
141
142 set boot_askname
143
144 Instructs the kernel to prompt the user for the name of the root device
145 when the kernel is booted.
146
147################################################################################
148# Tset Sboot_ddb DDrop to the kernel debugger (DDB)
149
150 set boot_ddb
151
152 Instructs the kernel to start in the DDB debugger, rather than
153 proceeding to initialise when booted.
154
155################################################################################
156# Tset Sboot_gdb DSelect gdb-remote mode
157
158 set boot_gdb
159
160 Selects gdb-remote mode for the kernel debugger by default.
161
162################################################################################
163# Tset Sboot_single DStart system in single-user mode
164
165 set boot_single
166
167 Prevents the kernel from initiating a multi-user startup, single-user
168 mode will be entered when the kernel has finished device probes.
169
170################################################################################
171# Tset Sboot_verbose DVerbose boot messages
172
173 set boot_verbose
174
175 Setting this variable causes extra debugging information to be printed
176 by the kernel during the boot phase.
177
178################################################################################
179# Tset Sconsole DSet the current console
180
181 set console[=<value>]
182
183 Sets the current console. If <value> is omitted, a list of valid
184 consoles will be displayed.
185
186################################################################################
187# Tset Scurrdev DSet the current device
188
189 set currdev=<device>
190
bc65ccee 191 Selects the default device. See lsdev for available devices.
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192
193################################################################################
194# Tset Sinit_path DSet the list of init candidates
195
196 set init_path=<path>[:<path>...]
197
198 Sets the list of binaries which the kernel will try to run as initial
199 process.
200
201
202################################################################################
203# Tset Smodule_path DSet the module search path
204
205 set module_path=<path>[;<path>...]
206
207 Sets the list of directories which will be searched in for modules
208 named in a load command or implicitly required by a dependency. The
f4e821f3 209 default module_path is "/boot;/boot/modules;/;/modules".
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210
211################################################################################
212# Tset Sprompt DSet the command prompt
213
214 set prompt=<value>
215
216 The command prompt is displayed when the loader is waiting for input.
217 Variable substitution is performed on the prompt. The default
218 prompt can be set with:
219
bc65ccee 220 set prompt=\${interpret}
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221
222################################################################################
223# Tset Srootdev DSet the root filesystem
224
225 set rootdev=<path>
226
227 By default the value of $currdev is used to set the root filesystem
228 when the kernel is booted. This can be overridden by setting
229 $rootdev explicitly.
230
231################################################################################
232# Tset Stunables DSet kernel tunable values
233
234 Various kernel tunable parameters can be overridden by specifying new
235 values in the environment.
236
237 set kern.ipc.nmbclusters=<value> NMBCLUSTERS
238
239 Set the number of mbuf clusters to be allocated. The value
240 cannot be set below the default determined when the kernel
241 was compiled.
242
4ad6607f 243 set kern.vm.kmem.size=<value>
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244
245 Sets the size of kernel memory (bytes). This overrides
5ee58eed 246 the value determined when the kernel was compiled.
984263bc 247
5ee58eed 248 set machdep.disable_mtrrs=1
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5ee58eed 250 Disable the use of i686 MTRRs (i386 only)
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251
252 set net.inet.tcp.tcbhashsize=<value> TCBHASHSIZE
253
254 Overrides the compile-time set value of TCBHASHSIZE or
255 the preset default of 512. Must be a power of 2.
256
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257 hw.syscons.sc_no_suspend_vtswitch=<value>
258
259 Disable VT switching on suspend.
260
261 value is 0 (default) or non-zero to enable.
262
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263 set hw.physmem=<value> MAXMEM (i386 only)
264
265 Limits the amount of physical memory space available to
266 the system to <value> bytes. <value> may have a k, M or G
267 suffix to indicate kilobytes, megabytes and gigabytes
268 respectively. Note that the current i386 architecture
269 limits this value to 4GB.
270
271 On systems where memory cannot be accurately probed,
272 this option provides a hint as to the actual size of
273 system memory (which will be tested before use).
274
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275 set hw.pci.allow_unsupported_io_range=<value>
276
277 Allow the PCI Bridge to pass through an unsupported
278 memory range assigned by the BIOS.
279
280 value is 0 (default) or non-zero to enable.
281
282 set hw.pci.enable_io_modes=<value>
283
284 Enable PCI resources which are left off by some BIOSes
285 or are not enabled correctly by the device driver.
286
287 value is 1 (default), but this may cause problems with
288 some peripherals. Set to 0 to disable.
289
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290################################################################################
291# Tshow DShow the values of variables
292
293 show [<variable>]
294
295 Displays the value of <variable>, or all variables if not specified.
296 Multiple paths can be separated with a semicolon.
297
298################################################################################
299# Tinclude DRead commands from a script file
300
301 include <filename> [<filename> ...]
302
303 The entire contents of <filename> are read into memory before executing
304 commands, so it is safe to source a file from removable media.
305
306################################################################################
307# Tread DRead input from the terminal
308
309 read [-t <value>] [-p <prompt>] [<variable name>]
310
311 The read command reads a line of input from the terminal. If the
312 -t argument is specified, it will return nothing if no input has been
313 received after <value> seconds. (Any keypress will cancel the
314 timeout).
315
316 If -p is specified, <prompt> is printed before reading input. No
317 newline is emitted after the prompt.
318
319 If a variable name is supplied, the variable is set to the value read,
320 less any terminating newline.
321
322################################################################################
323# Tunload DRemove all modules from memory
324
325 unload
326
327 This command removes any kernel and all loaded modules from memory.
328
329################################################################################
330# Tunset DUnset a variable
331
332 unset <variable name>
333
334 If allowed, the named variable's value is discarded and the variable
335 is removed.
336
337################################################################################