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

215 lines
6.8 KiB
Plaintext
Raw Normal View History

################################################################################
# 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.
################################################################################
# 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.
################################################################################
# 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.
################################################################################
# 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.
################################################################################
# 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.
################################################################################
# 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.
################################################################################
# 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.
################################################################################
# Tlsmod DList modules
lsmod [-v]
List loaded modules. If [-v] is specified, print more details.
################################################################################
# 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.
################################################################################
# Tset DSet a variable
set <variable name>
set <variable name>=<value>
The set command is used to set variables.
################################################################################
# Tset Sautboot_delay DSet the default autoboot delay
set autoboot_delay=<value>
Sets the default delay for the autoboot command to <value> seconds.
################################################################################
# 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.
################################################################################
# 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.
################################################################################
# Tset Scurrdev DSet the current device
set currdev=<device>
Selects the default device. Syntax for devices is odd.
################################################################################
# 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.
################################################################################
# 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>
################################################################################
# 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.
################################################################################
# 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.
################################################################################
# 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.
################################################################################
# Tunload DRemove all modules from memory
unload
This command removes any kernel and all loaded modules from memory.
################################################################################
# Tunset DUnset a variable
unset <variable name>
If allowed, the named variable's value is discarded and the variable
is removed.
################################################################################