1 ################################################################################
2 # Thelp DDisplay command help
4 help [topic [subtopic]]
7 The help command displays help on commands and their usage.
9 In command help, a term enclosed with <...> indicates a value as
10 described by the term. A term enclosed with [...] is optional,
11 and may not be required by all forms of the command.
13 Some commands may not be available. Use the '?' command to list
14 most available commands.
16 ################################################################################
17 # T? DList available commands
21 Lists all available commands.
23 ################################################################################
24 # Tautoboot DBoot after a delay
26 autoboot [<delay> [<prompt>]]
28 Displays <prompt> or a default prompt, and counts down <delay> seconds
29 before attempting to boot. If <delay> is not specified, the default
32 ################################################################################
33 # Tboot DBoot immediately
35 boot [<kernelname>] [-<arg> ...]
37 Boot the system. If arguments are specified, they are added to the
38 arguments for the kernel. If <kernelname> is specified, and a kernel
39 has not already been loaded, it will be booted instead of the default
42 ################################################################################
43 # Tbcachestat DGet disk block cache stats
47 Displays statistics about disk cache usage. For debugging only.
49 ################################################################################
50 # Techo DEcho arguments
54 Emits <message>, with no trailing newline if -n is specified. This is
55 most useful in conjunction with scripts and the '@' line prefix.
57 Variables are substituted by prefixing them with $, eg.
59 echo Current device is $currdev
61 will print the current device.
63 ################################################################################
64 # Tload DLoad a kernel or module
66 load [-t <type>] <filename>
68 Loads the module contained in <filename> into memory. If no other
69 modules are loaded, <filename> must be a kernel or the command will
72 If -t is specified, the module is loaded as raw data of <type>, for
73 later use by the kernel or other modules. <type> may be any string.
75 ################################################################################
80 Displays a listing of files in the directory <path>, or the root
81 directory of the current device if <path> is not specified.
83 The -l argument displays file sizes as well; the process of obtaining
84 file sizes on some media may be very slow.
86 ################################################################################
87 # Tlsdev DList devices
91 List all of the devices from which it may be possible to load modules.
92 If -v is specified, print more details.
94 ################################################################################
95 # Tlsmod DList modules
99 List loaded modules. If [-v] is specified, print more details.
101 ################################################################################
104 more <filename> [<filename> ...]
106 Show contents of text files. When displaying the contents of more,
107 than one file, if the user elects to quit displaying a file, the
108 remaining files will not be shown.
110 ################################################################################
111 # Tpnpscan DScan for PnP devices
115 Scan for Plug-and-Play devices. This command is normally automatically
116 run as part of the boot process, in order to dynamically load modules
117 required for system operation.
119 If the -v argument is specified, details on the devices found will
122 ################################################################################
123 # Tset DSet a variable
126 set <variable name>=<value>
128 The set command is used to set variables.
130 ################################################################################
131 # Tset Sautoboot_delay DSet the default autoboot delay
133 set autoboot_delay=<value>
135 Sets the default delay for the autoboot command to <value> seconds.
136 Set value to -1 if you don't want to allow user to interrupt autoboot
137 process and escape to the loader prompt.
139 ################################################################################
140 # Tset Sbootfile DSet the default boot file set
142 set bootfile=<filename>[;<filename>...]
144 Sets the default set of kernel boot filename(s). It may be overridden
145 by setting the bootfile variable to a semicolon-separated list of
146 filenames, each of which will be searched for in the module_path
147 directories. The default bootfile set is "kernel".
149 ################################################################################
150 # Tset Sboot_askname DPrompt for root device
154 Instructs the kernel to prompt the user for the name of the root device
155 when the kernel is booted.
157 ################################################################################
158 # Tset Sboot_cdrom DMount root file system from CD-ROM
162 Instructs the kernel to try to mount the root file system from CD-ROM.
164 ################################################################################
165 # Tset Sboot_ddb DDrop to the kernel debugger (DDB)
169 Instructs the kernel to start in the DDB debugger, rather than
170 proceeding to initialize when booted.
172 ################################################################################
173 # Tset Sboot_dfltroot DUse default root file system
177 Instructs the kernel to mount the statically compiled-in root
180 ################################################################################
181 # Tset Sboot_gdb DSelect gdb-remote mode for the kernel debugger
185 Selects gdb-remote mode for the kernel debugger by default.
187 ################################################################################
188 # Tset Sboot_multicons DUse multiple consoles
192 Enables multiple console support in the kernel early on boot.
193 In a running system, console configuration can be manipulated
194 by the conscontrol(8) utility.
196 ################################################################################
197 # Tset Sboot_mute DMute the console
201 All console output is suppressed when console is muted.
202 In a running system, the state of console muting can be
203 manipulated by the conscontrol(8) utility.
205 ################################################################################
206 # Tset Sboot_pause DPause after each line during device probing
210 During the device probe, pause after each line is printed.
212 ################################################################################
213 # Tset Sboot_serial DUse serial console
217 Force the use of a serial console even when an internal console
220 ################################################################################
221 # Tset Sboot_single DStart system in single-user mode
225 Prevents the kernel from initiating a multi-user startup; instead,
226 a single-user mode will be entered when the kernel has finished
229 ################################################################################
230 # Tset Sboot_verbose DVerbose boot messages
234 Setting this variable causes extra debugging information to be printed
235 by the kernel during the boot phase.
237 ################################################################################
238 # Tset Sconsole DSet the current console
240 set console[=<value>]
242 Sets the current console. If <value> is omitted, a list of valid
243 consoles will be displayed.
245 ################################################################################
246 # Tset Scurrdev DSet the current device
250 Selects the default device. See lsdev for available devices.
252 ################################################################################
253 # Tset Sinit_path DSet the list of init candidates
255 set init_path=<path>[:<path>...]
257 Sets the list of binaries which the kernel will try to run as initial
261 ################################################################################
262 # Tset Smodule_path DSet the module search path
264 set module_path=<path>[;<path>...]
266 Sets the list of directories which will be searched in for modules
267 named in a load command or implicitly required by a dependency. The
268 default module_path is "/boot/modules" with the kernel directory
271 ################################################################################
272 # Tset Sprompt DSet the command prompt
276 The command prompt is displayed when the loader is waiting for input.
277 Variable substitution is performed on the prompt. The default
278 prompt can be set with:
280 set prompt=\${interpret}
282 ################################################################################
283 # Tset Srootdev DSet the root filesystem
287 By default the value of $currdev is used to set the root filesystem
288 when the kernel is booted. This can be overridden by setting
291 ################################################################################
292 # Tset Stunables DSet kernel tunable values
294 Various kernel tunable parameters can be overridden by specifying new
295 values in the environment.
297 set kern.ipc.nmbclusters=<value>
299 Set the number of mbuf clusters to be allocated. The value
300 cannot be set below the default determined when the kernel
303 set kern.ipc.nsfbufs=<value> NSFBUFS
305 Set the number of sendfile buffers to be allocated. This
306 overrides the value determined when the kernel was compiled.
308 set vm.kmem_size=<value> VM_KMEM_SIZE
310 Sets the size of kernel memory (bytes). This overrides
311 the value determined when the kernel was compiled.
313 set machdep.disable_mtrrs=1
315 Disable the use of i686 MTRRs (i386 only)
317 set net.inet.tcp.tcbhashsize=<value> TCBHASHSIZE
319 Overrides the compile-time set value of TCBHASHSIZE or
320 the preset default of 512. Must be a power of 2.
322 hw.syscons.sc_no_suspend_vtswitch=<value>
324 Disable VT switching on suspend.
326 value is 0 (default) or non-zero to enable.
328 set hw.physmem=<value> MAXMEM (i386 only)
330 Limits the amount of physical memory space available to
331 the system to <value> bytes. <value> may have a k, M or G
332 suffix to indicate kilobytes, megabytes and gigabytes
333 respectively. Note that the current i386 architecture
334 limits this value to 4GB.
336 On systems where memory cannot be accurately probed,
337 this option provides a hint as to the actual size of
338 system memory (which will be tested before use).
340 set hw.{acpi,pci}.host_start_mem=<value>
342 Sets the lowest address that the pci code will assign
343 when it doesn't have other information about the address
344 to assign (like from a pci bridge). This is only useful
345 in older systems without a pci bridge. Also, it only
346 impacts devices that the BIOS doesn't assign to, typically
347 CardBus bridges. The default <value> is 0x80000000, but
348 some systems need values like 0xf0000000, 0xfc000000 or
349 0xfe000000 may be suitable for older systems (the older
350 the system, the higher the number typically should be).
352 set hw.pci.enable_io_modes=<value>
354 Enable PCI resources which are left off by some BIOSes
355 or are not enabled correctly by the device driver.
357 value is 1 (default), but this may cause problems with
358 some peripherals. Set to 0 to disable.
360 ################################################################################
361 # Tshow DShow the values of variables
365 Displays the value of <variable>, or all variables if not specified.
366 Multiple paths can be separated with a semicolon.
368 ################################################################################
369 # Tinclude DRead commands from a script file
371 include <filename> [<filename> ...]
373 The entire contents of <filename> are read into memory before executing
374 commands, so it is safe to source a file from removable media.
376 ################################################################################
377 # Tread DRead input from the terminal
379 read [-t <value>] [-p <prompt>] [<variable name>]
381 The read command reads a line of input from the terminal. If the
382 -t argument is specified, it will return nothing if no input has been
383 received after <value> seconds. (Any keypress will cancel the
386 If -p is specified, <prompt> is printed before reading input. No
387 newline is emitted after the prompt.
389 If a variable name is supplied, the variable is set to the value read,
390 less any terminating newline.
392 ################################################################################
393 # Tunload DRemove all modules from memory
397 This command removes any kernel and all loaded modules from memory.
399 ################################################################################
400 # Tunset DUnset a variable
402 unset <variable name>
404 If allowed, the named variable's value is discarded and the variable
407 ################################################################################