busybox.pod

手机嵌入式Linux下可用的busybox源码

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=item B<dumpkmap>

dumpkmap > keymap

Prints out a binary keyboard translation table to standard output.

Example:

	$ dumpkmap > keymap

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=item B<dutmp>

dutmp [FILE]

Dump utmp file format (pipe delimited) from FILE
or stdin to stdout.  (i.e., 'dutmp /var/run/utmp')

Example:

	$ dutmp /var/run/utmp
	8|7||si|||0|0|0|955637625|760097|0
	2|0|~|~~|reboot||0|0|0|955637625|782235|0
	1|20020|~|~~|runlevel||0|0|0|955637625|800089|0
	8|125||l4|||0|0|0|955637629|998367|0
	6|245|tty1|1|LOGIN||0|0|0|955637630|998974|0
	6|246|tty2|2|LOGIN||0|0|0|955637630|999498|0
	7|336|pts/0|vt00andersen|andersen|:0.0|0|0|0|955637763|0|0

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=item B<echo>

echo [B<-neE>] [ARG ...]

Prints the specified ARGs to stdout

Options:

	-n	suppress trailing newline
	-e	interpret backslash-escaped characters (i.e., \t=tab)
	-E	disable interpretation of backslash-escaped characters

Example:

	$ echo "Erik is cool"
	Erik is cool
	$  echo -e "Erik\nis\ncool"
	Erik
	is
	cool
	$ echo "Erik\nis\ncool"
	Erik\nis\ncool

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=item B<env>

env [B<-iu>] [-] [name=value]... [command]

Prints the current environment or runs a program after setting
up the specified environment.

Options:

	-, -i	start with an empty environment
	-u	remove variable from the environment

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=item B<expr>

expr EXPRESSION

Prints the value of EXPRESSION to standard output.

EXPRESSION may be:

	ARG1 |  ARG2	ARG1 if it is neither null nor 0, otherwise ARG2
	ARG1 &  ARG2	ARG1 if neither argument is null or 0, otherwise 0
	ARG1 <  ARG2	ARG1 is less than ARG2
	ARG1 <= ARG2	ARG1 is less than or equal to ARG2
	ARG1 =  ARG2	ARG1 is equal to ARG2
	ARG1 != ARG2	ARG1 is unequal to ARG2
	ARG1 >= ARG2	ARG1 is greater than or equal to ARG2
	ARG1 >  ARG2	ARG1 is greater than ARG2
	ARG1 +  ARG2	arithmetic sum of ARG1 and ARG2
	ARG1 -  ARG2	arithmetic difference of ARG1 and ARG2
	ARG1 *  ARG2	arithmetic product of ARG1 and ARG2
	ARG1 /  ARG2	arithmetic quotient of ARG1 divided by ARG2
	ARG1 %  ARG2	arithmetic remainder of ARG1 divided by ARG2
	STRING : REGEXP             anchored pattern match of REGEXP in STRING
	match STRING REGEXP         same as STRING : REGEXP
	substr STRING POS LENGTH    substring of STRING, POS counted from 1
	index STRING CHARS          index in STRING where any CHARS is found,
	                            or 0
	length STRING               length of STRING
	quote TOKEN                 interpret TOKEN as a string, even if
	                            it is a keyword like `match' or an
	                            operator like `/'
	( EXPRESSION )              value of EXPRESSION

Beware that many operators need to be escaped or quoted for shells.
Comparisons are arithmetic if both ARGs are numbers, else
lexicographical.  Pattern matches return the string matched between 
\( and \) or null; if \( and \) are not used, they return the number 
of characters matched or 0.

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=item B<false>

false 	

Return an exit code of FALSE (1).

Example:

	$ false
	$ echo $?
	1

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=item B<fbset>

fbset [options] [mode]

Show and modify frame buffer settings

Example:

	$ fbset
	mode "1024x768-76"
		# D: 78.653 MHz, H: 59.949 kHz, V: 75.694 Hz
		geometry 1024 768 1024 768 16
		timings 12714 128 32 16 4 128 4
		accel false
		rgba 5/11,6/5,5/0,0/0
	endmode

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=item B<fdflush>

fdflush DEVICE

Forces floppy disk drive to detect disk change

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=item B<find>

find [PATH...] [EXPRESSION]

Search for files in a directory hierarchy.  The default PATH is
the current directory; default EXPRESSION is 'B<-print>'

EXPRESSION may consist of:

	-follow		Dereference symbolic links.
	-name PATTERN	File name (leading directories removed) matches PATTERN.
	-print		Print (default and assumed).

	-type X		Filetype matches X (where X is one of: f,d,l,b,c,...)
	-perm PERMS	Permissions match any of (+NNN); all of (-NNN);
			or exactly (NNN)
	-mtime TIME	Modified time is greater than (+N); less than (-N);
			or exactly (N) days
	-newer FILE	Modified time is more recent than FILE's

Example:

	$ find / -name /etc/passwd
	/etc/passwd

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=item B<free>

free 	

Displays the amount of free and used system memory

Example:

	$ free
	              total         used         free       shared      buffers
	  Mem:       257628       248724         8904        59644        93124
	 Swap:       128516         8404       120112
	Total:       386144       257128       129016

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=item B<freeramdisk>

freeramdisk DEVICE

Frees all memory used by the specified ramdisk.

Example:

	$ freeramdisk /dev/ram2

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=item B<fsck_minix>

fsck_minix [B<-larvsmf>] /dev/name

Performs a consistency check for MINIX filesystems.

Options:

	-l	Lists all filenames
	-r	Perform interactive repairs
	-a	Perform automatic repairs
	-v	verbose
	-s	Outputs super-block information
	-m	Activates MINIX-like "mode not cleared" warnings
	-f	Force file system check.

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=item B<getopt>

getopt [OPTIONS]...

Parse command options

	-a, --alternative		Allow long options starting with single -
	-l, --longoptions=longopts	Long options to be recognized
	-n, --name=progname		The name under which errors are reported
	-o, --options=optstring	Short options to be recognized
	-q, --quiet			Disable error reporting by getopt(3)
	-Q, --quiet-output		No normal output
	-s, --shell=shell		Set shell quoting conventions
	-T, --test			Test for getopt(1) version
	-u, --unqote			Do not quote the output

Example:

	$ cat getopt.test
	#!/bin/sh
	GETOPT=`getopt -o ab:c:: --long a-long,b-long:,c-long:: \
	       -n 'example.busybox' -- "$@"`
	if [ $? != 0 ] ; then  exit 1 ; fi
	eval set -- "$GETOPT"
	while true ; do
	 case $1 in
	   -a|--a-long) echo "Option a" ; shift ;;
	   -b|--b-long) echo "Option b, argument `$2'" ; shift 2 ;;
	   -c|--c-long)
	     case "$2" in
	       "") echo "Option c, no argument"; shift 2 ;;
	       *)  echo "Option c, argument `$2'" ; shift 2 ;;
	     esac ;;
	   --) shift ; break ;;
	   *) echo "Internal error!" ; exit 1 ;;
	 esac
	done

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=item B<grep>

grep [B<-ihHnqvs>] PATTERN [FILEs...]

Search for PATTERN in each FILE or standard input.

Options:

	-H	prefix output lines with filename where match was found
	-h	suppress the prefixing filename on output
	-i	ignore case distinctions
	-l	list names of files that match
	-n	print line number with output lines
	-q	be quiet. Returns 0 if result was found, 1 otherwise
	-v	select non-matching lines
	-s	suppress file open/read error messages

Example:

	$ grep root /etc/passwd
	root:x:0:0:root:/root:/bin/bash
	$ grep ^[rR]oo. /etc/passwd
	root:x:0:0:root:/root:/bin/bash

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=item B<gunzip>

gunzip [OPTION]... FILE

Uncompress FILE (or standard input if FILE is '-').

Options:

	-c	Write output to standard output
	-t	Test compressed file integrity

Example:

	$ ls -la /tmp/BusyBox*
	-rw-rw-r--    1 andersen andersen   557009 Apr 11 10:55 /tmp/BusyBox-0.43.tar.gz
	$ gunzip /tmp/BusyBox-0.43.tar.gz
	$ ls -la /tmp/BusyBox*
	-rw-rw-r--    1 andersen andersen  1761280 Apr 14 17:47 /tmp/BusyBox-0.43.tar

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=item B<gzip>

gzip [OPTION]... FILE

Compress FILE with maximum compression.
When FILE is '-', reads standard input.  Implies B<-c>.

Options:

	-c	Write output to standard output instead of FILE.gz
	-d	decompress

Example:

	$ ls -la /tmp/busybox*
	-rw-rw-r--    1 andersen andersen  1761280 Apr 14 17:47 /tmp/busybox.tar
	$ gzip /tmp/busybox.tar
	$ ls -la /tmp/busybox*
	-rw-rw-r--    1 andersen andersen   554058 Apr 14 17:49 /tmp/busybox.tar.gz

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=item B<halt>

halt 	

Halt the system.

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=item B<head>

head [OPTION] [FILE]...

Print first 10 lines of each FILE to standard output.
With more than one FILE, precede each with a header giving the
file name. With no FILE, or when FILE is -, read standard input.

Options:

	-n NUM		Print first NUM lines instead of first 10

Example:

	$ head -n 2 /etc/passwd
	root:x:0:0:root:/root:/bin/bash
	daemon:x:1:1:daemon:/usr/sbin:/bin/sh

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=item B<hostid>

hostid 	

Print out a unique 32-bit identifier for the machine.

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=item B<hostname>

hostname [OPTION] {hostname | B<-F> FILE}

Get or set the hostname or DNS domain name. If a hostname is given
(or FILE with the B<-F> parameter), the host name will be set.

Options:

	-s		Short
	-i		Addresses for the hostname
	-d		DNS domain name
	-F, --file FILE	Use the contents of FILE to specify the hostname

Example:

	$ hostname
	sage 

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=item B<id>

id [OPTIONS]... [USERNAME]

Print information for USERNAME or the current user

Options:

	-g	prints only the group ID
	-u	prints only the user ID
	-n	print a name instead of a number (with for -ug)
	-r	prints the real user ID instead of the effective ID (with -ug)

Example:

	$ id
	uid=1000(andersen) gid=1000(andersen)

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=item B<ifconfig>

ifconfig [B<-a>] <interface> [<address>]

configure a network interface

Options:

	[[-]broadcast [<address>]]  [[-]pointopoint [<address>]]
	[netmask <address>]  [dstaddr <address>]
	[outfill <NN>] [keepalive <NN>]
	[hw ether <address>]  [metric <NN>]  [mtu <NN>]
	[[-]trailers]  [[-]arp]  [[-]allmulti]
	[multicast]  [[-]promisc]  [txqueuelen <NN>]  [[-]dynamic]
	[mem_start <NN>]  [io_addr <NN>]  [irq <NN>]
	[up|down] ...

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=item B<init>

init 	

Init is the parent of all processes.

This version of init is designed to be run only by the kernel.

BusyBox init doesn't support multiple runlevels.  The runlevels field of
the /etc/inittab file is completely ignored by BusyBox init. If you want 
runlevels, use sysvinit.

BusyBox init works just fine without an inittab.  If no inittab is found, 
it has the following default behavior:

	::sysinit:/etc/init.d/rcS
	::askfirst:/bin/sh
	::ctrlaltdel:/sbin/reboot
	::shutdown:/sbin/swapoff -a
	::shutdown:/bin/umount -a -r
	::restart:/sbin/init

if it detects that /dev/console is _not_ a serial console, it will also run:

	tty2::askfirst:/bin/sh
	tty3::askfirst:/bin/sh
	tty4::askfirst:/bin/sh

If you choose to use an /etc/inittab file, the inittab entry format is as follows:

	<id>:<runlevels>:<action>:<process>

	<id>: 

		WARNING: This field has a non-traditional meaning for BusyBox init!
		The id field is used by BusyBox init to specify the controlling tty for
		the specified process to run on.  The contents of this field are
		appended to "/dev/" and used as-is.  There is no need for this field to
		be unique, although if it isn't you may have strange results.  If this
		field is left blank, the controlling tty is set to the console.  Also
		note that if BusyBox detects that a serial console is in use, then only
		entries whose controlling tty is either the serial console or /dev/null
		will be run.  BusyBox init does nothing with utmp.  We don't need no
		stinkin' utmp.

	<runlevels>: 

		The runlevels field is completely ignored.

	<action>: 

		Valid actions include: sysinit, respawn, askfirst, wait, 
		once, restart, ctrlaltdel, and shutdown.

		The available actions can be classified into two groups: actions
		that are run only once, and actions that are re-run when the specified
		process exits.

		Run only-once actions:

			'sysinit' is the first item run on boot.  init waits until all
			sysinit actions are completed before continuing.  Following the
			completion of all sysinit actions, all 'wait' actions are run.
			'wait' actions, like  'sysinit' actions, cause init to wait until
			the specified task completes.  'once' actions are asynchronous,
			therefore, init does not wait for them to complete.  'restart' is
			the action taken to restart the init process.  By default this should
			simply run /sbin/init, but can be a script which runs pivot_root or it
			can do all sorts of other interesting things.  The 'ctrlaltdel' init
			actions are run when the system detects that someone on the system
                       console has pressed the CTRL-ALT-DEL key combination.  Typically one
                       wants to run 'reboot' at this point to cause the system to reboot.
			Finally the 'shutdown' action specifies the actions to taken when
                       init is told to reboot.  Unmounting filesystems and disabling swap
                       is a very good here

		Run repeatedly actions:

			'respawn' actions are run after the 'once' actions.  When a process
			started with a 'respawn' action exits, init automatically restarts