freebsd-dev/sys/boot/common/help.common

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# Thelp DDisplay command help

	help [topic [subtopic]]
	?

	The help command displays help on commands and their usage.

	In command help, a term enclosed with <...> indicates a value as
	described by the term.  A term enclosed with [...] is optional,
	and may not be required by all forms of the command.

	Some commands may not be availalble.  Use the '?' command to list
	most available commands.

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# Tautoboot DBoot after a delay

	autoboot [<delay> [<prompt>]]

	Displays <prompt> or a default prompt, and counts down <delay> seconds
	before attempting to boot.  If <delay> is not specified, the default
	value is 10.

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# Tboot DBoot immediately

	boot [-<arg> ...] [<kernelname>]

	Boot the system.  If arguments are specified, they are added to the
	arguments for the kernel.  If <kernelname> is specified, and a kernel
	has not already been loaded, it will be booted instead of the default
	kernel.

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# Techo DEcho arguments

	echo [-n] [<message>]

	Emits <message>, with no trailing newline if -n is specified.  This is
	most useful in conjunction with scripts and the '@' line prefix.

	Variables are substituted by prefixing them with $, eg.

		echo Current device is $currdev

	will print the current device.

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# Tload DLoad a kernel or module
	
	load [-t <type>] <filename>

	Loads the module contained in <filename> into memory.  If no other
	modules are loaded, <filename> must be a kernel or the command will
	fail.

	If -t is specified, the module is loaded as raw data of <type>, for
	later use by the kernel or other modules.  <type> may be any string.

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# Tls DList files

	ls [-l] [<path>]

	Displays a listing of files in the directory <path>, or the root
	directory of the current device if <path> is not specified.

	The -l argument displays file sizes as well; the process of obtaining
	file sizes on some media may be very slow.

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# Tlsdev DList devices

	lsdev [-v]

	List all of the devices from which it may be possible to load modules.
	If -v is specified, print more details.

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# Tlsmod DList modules

	lsmod [-v]

	List loaded modules. If [-v] is specified, print more details.

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# Tpnpscan DScan for PnP devices

	pnpscan [-v]

	Scan for Plug-and-Play devices.  This command is normally automatically
	run as part of the boot process, in order to dynamically load modules
	required for system operation.

	If the -v argument is specified, details on the devices found will
	be printed.

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# Tset DSet a variable

	set <variable name>
	set <variable name>=<value>

	The set command is used to set variables.

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# Tset Sautoboot_delay DSet the default autoboot delay

	set autoboot_delay=<value>

	Sets the default delay for the autoboot command to <value> seconds.

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# Tset Sbootfile DSet the default boot file set

	set bootfile=<filename>[,<filename>...]

	The default search path for bootable kernels is /kernel,/kernel.old.
	It may be overridden by setting the bootfile variable to a 
	semicolon-separated list of paths, which will be searched for in turn.

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# Tset Sboot_askname DPrompt for root device when kernel is booted

	set boot_askname

	Instructs the kernel to prompt the user for the name of the root device
	when the kernel is booted.

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# Tset Sboot_ddb DDrop to the kernel debugger (DDB) when the kernel is loaded

	set boot_ddb

	Instructs the kernel to start in the DDB debugger, rather than
	proceeding to initialise when booted.

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# Tset Sboot_gdb DSelect gdb-remote mode for kernel debugger

	set boot_gdb

	Selects gdb-remote mode for the kernel debugger by default.

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# Tset Sboot_single DRequest the kernel start in single-user mode

	set boot_single

	Prevents the kernel from initiating a multi-user startup, single-user
	mode will be entered when the kernel has finished device probes.

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# Tset Sboot_verbose DDisplay verbose device probes and debugging information

	set boot_verbose

	Setting this variable causes extra debugging information to be printed
	by the kernel during the boot phase.

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# Tset Sconsole DSet the current console

	set console[=<value>]

	Sets the current console.  If <value> is omitted, a list of valid
	consoles will be displayed.

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# Tset Scurrdev DSet the current device

	set currdev=<device>

	Selects the default device.  Syntax for devices is odd.

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# Tset Smodule_path DSet the module search path

	set module_path=<path>[,<path>...]

	Sets the list of directories which will be searched in for modules
	named in a load command or implicitly required by a dependancy.

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# Tset Sprompt DSet the command prompt

	set prompt=<value>

	The command prompt is displayed when the loader is waiting for input.
	Variable substitution is performed on the prompt.  The default 
	prompt can be set with:

		set prompt=\$currdev>

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# Tset Srootdev DSet the root filesystem

	set rootdev=<path>

	By default the value of $currdev is used to set the root filesystem
	when the kernel is booted.  This can be overridden by setting
	$rootdev explicitly.

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# Tshow DShow the values of variables

	show [<variable>]

	Displays the value of <variable>, or all variables if not specified.
	Multiple paths can be separated with a semicolon.

	See the set command for a list of some variables.

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# Tsource DRead commands from a script file

	source <filename>

	The entire contents of <filename> are read into memory before executing
	commands, so it is safe to source a file from removable media.

	A number of modifiers may be prefixed to commands within a script file
	to alter their behaviour:

	@	Suppresses the printing of the command when executed.

	-	Prevents the script from terminating if the command returns
		an error.

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# Tread DRead input from the terminal

	read [-t <value>] [-p <prompt>] [<variable name>]

	The read command reads a line of input from the terminal.  If the 
	-t argument is specified, it will return nothing if no input has been
	received after <value> seconds.  (Any keypress will cancel the 
	timeout).

	If -p is specified, <prompt> is printed before reading input. No 
	newline is emitted after the prompt.

	If a variable name is supplied, the variable is set to the value read,
	less any terminating newline.

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# Tunload DRemove all modules from memory

	unload

	This command removes any kernel and all loaded modules from memory.

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# Tunset DUnset a variable

	unset <variable name>

	If allowed, the named variable's value is discarded and the variable
	is removed.	

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