BusyBox - The Swiss Army Knife of Embedded Linux
BusyBox <function> [arguments...] # or
<function> [arguments...] # if symlinked
BusyBox combines tiny versions of many common UNIX utilities into a single small executable. It provides minimalist replacements for most of the utilities you usually find in fileutils, shellutils, findutils, textutils, grep, gzip, tar, etc. BusyBox provides a fairly complete POSIX environment for any small or embedded system. The utilities in BusyBox generally have fewer options than their full-featured GNU cousins; however, the options that are included provide the expected functionality and behave very much like their GNU counterparts.
BusyBox has been written with size-optimization and limited resources in mind. It is also extremely modular so you can easily include or exclude commands (or features) at compile time. This makes it easy to customize your embedded systems. To create a working system, just add a kernel, a shell (such as ash), and an editor (such as elvis-tiny or ae).
When you create a link to BusyBox for the function you wish to use, when BusyBox is called using that link it will behave as if the command itself has been invoked.
For example, entering
ln -s ./BusyBox ls
./ls
will cause BusyBox to behave as 'ls' (if the 'ls' command has been compiled into BusyBox).
You can also invoke BusyBox by issuing the command as an argument on the command line. For example, entering
./BusyBox ls
will also cause BusyBox to behave as 'ls'.
Most BusyBox commands support the -h option to provide a terse runtime description of their behavior.
Currently defined functions include:
adjtimex, ar, basename, busybox, cat, chgrp, chmod, chown, chroot, chvt, clear, cmp, cp, cpio, cut, date, dc, dd, deallocvt, df, dirname, dmesg, dos2unix, dpkg, dpkg-deb, du, dumpkmap, dutmp, echo, expr, false, fbset, fdflush, find, free, freeramdisk, fsck.minix, getopt, grep, gunzip, gzip, halt, head, hostid, hostname, id, ifconfig, init, insmod, kill, killall, klogd, length, ln, loadacm, loadfont, loadkmap, logger, logname, ls, lsmod, makedevs, md5sum, mkdir, mkfifo, mkfs.minix, mknod, mkswap, mktemp, more, mount, mt, mv, nc, nslookup, ping, pivot_root, poweroff, printf, ps, pwd, rdate, readlink, reboot, renice, reset, rm, rmdir, rmmod, route, rpm2cpio, sed, setkeycodes, sh, sleep, sort, stty, swapoff, swapon, sync, syslogd, tail, tar, tee, telnet, test, tftp, touch, tr, true, tty, umount, uname, uniq, unix2dos, update, uptime, usleep, uudecode, uuencode, watchdog, wc, wget, which, whoami, xargs, yes, zcat, [
Reads and optionally sets system timebase parameters. See adjtimex(2).
Options:
-q quiet mode - do not print
-o offset time offset, microseconds
-f frequency frequency adjust, integer kernel units (65536 is 1ppm)
(positive values make the system clock run fast)
-t tick microseconds per tick, usually 10000
-p timeconstant
-------------------------------
Extract or list FILES from an ar archive.
Options:
-o preserve original dates
-p extract to stdout
-t list
-x extract
-v verbosely list files processed
-------------------------------
Strips directory path and suffixes from FILE. If specified, also removes any trailing SUFFIX.
Example:
$ basename /usr/local/bin/foo
foo
$ basename /usr/local/bin/
bin
$ basename /foo/bar.txt .txt
bar
-------------------------------
Concatenates FILE(s) and prints them to stdout.
Example:
$ cat /proc/uptime
110716.72 17.67
-------------------------------
Change the group membership of each FILE to GROUP.
Options:
-R Changes files and directories recursively.
Example:
$ ls -l /tmp/foo
-r--r--r-- 1 andersen andersen 0 Apr 12 18:25 /tmp/foo
$ chgrp root /tmp/foo
$ ls -l /tmp/foo
-r--r--r-- 1 andersen root 0 Apr 12 18:25 /tmp/foo
-------------------------------
Each MODE is one or more of the letters ugoa, one of the symbols +-= and one or more of the letters rwxst.
Options:
-R Changes files and directories recursively.
Example:
$ ls -l /tmp/foo
-rw-rw-r-- 1 root root 0 Apr 12 18:25 /tmp/foo
$ chmod u+x /tmp/foo
$ ls -l /tmp/foo
-rwxrw-r-- 1 root root 0 Apr 12 18:25 /tmp/foo*
$ chmod 444 /tmp/foo
$ ls -l /tmp/foo
-r--r--r-- 1 root root 0 Apr 12 18:25 /tmp/foo
-------------------------------
Change the owner and/or group of each FILE to OWNER and/or GROUP.
Options:
-R Changes files and directories recursively.
-h Do not dereference symbolic links.
Example:
$ ls -l /tmp/foo
-r--r--r-- 1 andersen andersen 0 Apr 12 18:25 /tmp/foo
$ chown root /tmp/foo
$ ls -l /tmp/foo
-r--r--r-- 1 root andersen 0 Apr 12 18:25 /tmp/foo
$ chown root.root /tmp/foo
ls -l /tmp/foo
-r--r--r-- 1 root root 0 Apr 12 18:25 /tmp/foo
-------------------------------
Run COMMAND with root directory set to NEWROOT.
Example:
$ ls -l /bin/ls
lrwxrwxrwx 1 root root 12 Apr 13 00:46 /bin/ls -> /BusyBox
$ mount /dev/hdc1 /mnt -t minix
$ chroot /mnt
$ ls -l /bin/ls
-rwxr-xr-x 1 root root 40816 Feb 5 07:45 /bin/ls*
-------------------------------
Changes the foreground virtual terminal to /dev/ttyN
-------------------------------
Clear screen.
-------------------------------
-s quiet mode - do not print
Compare files.
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Copies SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY.
-a Same as -dpR
-d Preserves links
-p Preserves file attributes if possible
-f force (implied; ignored) - always set
-R Copies directories recursively
-------------------------------
Extract or list files from a cpio archive Main operation mode:
d make leading directories
i extract
m preserve mtime
t list
u unconditional overwrite F input from file
-------------------------------
Prints selected fields from each input FILE to standard output.
Options:
-b LIST Output only bytes from LIST
-c LIST Output only characters from LIST
-d CHAR Use CHAR instead of tab as the field delimiter
-s Output only the lines containing delimiter
-f N Print only these fields
-n Ignored
Example:
$ echo "Hello world" | cut -f 1 -d ' '
Hello
$ echo "Hello world" | cut -f 2 -d ' '
world
-------------------------------
Displays the current time in the given FORMAT, or sets the system date.
Options:
-R Outputs RFC-822 compliant date string
-d STRING display time described by STRING, not `now'
-s Sets time described by STRING
-u Prints or sets Coordinated Universal Time
Example:
$ date
Wed Apr 12 18:52:41 MDT 2000
-------------------------------
This is a Tiny RPN calculator that understands the following operations: +, -, /, *, and, or, not, eor. i.e., 'dc 2 2 add' -> 4, and 'dc 8 8 \* 2 2 + /' -> 16
Example:
$ dc 2 2 +
4
$ dc 8 8 * 2 2 + /
16
$ dc 0 1 and
0
$ dc 0 1 or
1
$ echo 72 9 div 8 mul | dc
64
-------------------------------
| dd [if=FILE] [of=FILE] [bs=N] [count=N] [skip=N] | |
| [seek=N] [conv=notrunc|noerror|sync] |
Copy a file, converting and formatting according to options
if=FILE read from FILE instead of stdin
of=FILE write to FILE instead of stdout
bs=N read and write N bytes at a time
count=N copy only N input blocks
skip=N skip N input blocks
seek=N skip N output blocks
conv=notrunc don't truncate output file
conv=noerror continue after read errors
conv=sync pad blocks with zeros
Numbers may be suffixed by c (x1), w (x2), b (x512), kD (x1000), k (x1024), MD (x1000000), M (x1048576), GD (x1000000000) or G (x1073741824).
Example:
$ dd if=/dev/zero of=/dev/ram1 bs=1M count=4
4+0 records in
4+0 records out
-------------------------------
Deallocate unused virtual terminal /dev/ttyN
-------------------------------
Print the filesystem space used and space available.
Options:
-h print sizes in human readable format (e.g., 1K 243M 2G )
-m print sizes in megabytes
-k print sizes in kilobytes(default)
Example:
$ df
Filesystem 1k-blocks Used Available Use% Mounted on
/dev/sda3 8690864 8553540 137324 98% /
/dev/sda1 64216 36364 27852 57% /boot
$ df /dev/sda3
Filesystem 1k-blocks Used Available Use% Mounted on
/dev/sda3 8690864 8553540 137324 98% /
-------------------------------
Strips non-directory suffix from FILENAME
Example:
$ dirname /tmp/foo
/tmp
$ dirname /tmp/foo/
/tmp
-------------------------------
Prints or controls the kernel ring buffer
Options:
-c Clears the ring buffer's contents after printing
-n LEVEL Sets console logging level
-s SIZE Use a buffer of size SIZE
-------------------------------
Converts FILE from dos format to unix format. When no option is given, the input is converted to the opposite output format. When no file is given, uses stdin for input and stdout for output.
Options:
-u output will be in UNIX format
-d output will be in DOS format
-------------------------------
-i Install the package
-C Configure an unpackaged package
-P Purge all files of a package
-r Remove all but the configuration files for a package
-u Unpack a package, but dont configure it
-------------------------------
Perform actions on debian packages (.debs)
Options:
-c List contents of filesystem tree
-e Extract control files to [argument] directory
-f Display control field name starting with [argument]
-I Display the control filenamed [argument]
-t Extract filesystem tree to stdout in tar format
-x Extract packages filesystem tree to directory
-X Verbose extract
Example:
$ dpkg-deb -X ./busybox_0.48-1_i386.deb /tmp
-------------------------------
Summarizes disk space used for each FILE and/or directory. Disk space is printed in units of 1024 bytes.
Options:
-l count sizes many times if hard linked
-s display only a total for each argument
-h print sizes in human readable format (e.g., 1K 243M 2G )
-m print sizes in megabytes
-x skip directories on different filesystems
-k print sizes in kilobytes(default)
Example:
$ du
16 ./CVS
12 ./kernel-patches/CVS
80 ./kernel-patches
12 ./tests/CVS
36 ./tests
12 ./scripts/CVS
16 ./scripts
12 ./docs/CVS
104 ./docs
2417 .
-------------------------------
Prints out a binary keyboard translation table to standard output.
Example:
$ dumpkmap > keymap
-------------------------------
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
-------------------------------
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
-------------------------------
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
-------------------------------
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.
-------------------------------
Return an exit code of FALSE (1).
Example:
$ false
$ echo $?
1
-------------------------------
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
-------------------------------
Forces floppy disk drive to detect disk change
-------------------------------
Search for files in a directory hierarchy. The default PATH is the current directory; default EXPRESSION is '-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
-------------------------------
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
-------------------------------
Frees all memory used by the specified ramdisk.
Example:
$ freeramdisk /dev/ram2
-------------------------------
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.
-------------------------------
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
-------------------------------
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
-------------------------------
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
-------------------------------
Compress FILE with maximum compression. When FILE is '-', reads standard input. Implies -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
-------------------------------
Halt the system.
-------------------------------
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
-------------------------------
Print out a unique 32-bit identifier for the machine.
-------------------------------
Get or set the hostname or DNS domain name. If a hostname is given (or FILE with the -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
-------------------------------
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)
-------------------------------
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] ...
-------------------------------
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
it. Unlike sysvinit, BusyBox init does not stop processes from
respawning out of control. The 'askfirst' actions acts just like
respawn, except that before running the specified process it
displays the line "Please press Enter to activate this console."
and then waits for the user to press enter before starting the
specified process.
Unrecognized actions (like initdefault) will cause init to emit an
error message, and then go along with its business. All actions are
run in the reverse order from how they appear in /etc/inittab.
<process>:
Specifies the process to be executed and it's command line.
Example /etc/inittab file:
# This is run first except when booting in single-user mode.
#
::sysinit:/etc/init.d/rcS
# /bin/sh invocations on selected ttys
#
# Start an "askfirst" shell on the console (whatever that may be)
::askfirst:-/bin/sh
# Start an "askfirst" shell on /dev/tty2-4
tty2::askfirst:-/bin/sh
tty3::askfirst:-/bin/sh
tty4::askfirst:-/bin/sh
# /sbin/getty invocations for selected ttys
#
tty4::respawn:/sbin/getty 38400 tty5
tty5::respawn:/sbin/getty 38400 tty6
# Example of how to put a getty on a serial line (for a terminal)
#
#::respawn:/sbin/getty -L ttyS0 9600 vt100
#::respawn:/sbin/getty -L ttyS1 9600 vt100
#
# Example how to put a getty on a modem line.
#::respawn:/sbin/getty 57600 ttyS2
# Stuff to do when restarting the init process
::restart:/sbin/init
# Stuff to do before rebooting
::ctrlaltdel:/sbin/reboot
::shutdown:/bin/umount -a -r
::shutdown:/sbin/swapoff -a
-------------------------------
Loads the specified kernel modules into the kernel.
Options:
-f Force module to load into the wrong kernel version.
-k Make module autoclean-able.
-v verbose output
-L Lock to prevent simultaneous loads of a module
-x do not export externs
-------------------------------
Send a signal (default is SIGTERM) to the specified process(es).
Options:
-l List all signal names and numbers.
Example:
$ ps | grep apache
252 root root S [apache]
263 www-data www-data S [apache]
264 www-data www-data S [apache]
265 www-data www-data S [apache]
266 www-data www-data S [apache]
267 www-data www-data S [apache]
$ kill 252
-------------------------------
Send a signal (default is SIGTERM) to the specified process(es).
Options:
-l List all signal names and numbers.
Example:
$ killall apache
-------------------------------
Kernel logger. Options:
-n Run as a foreground process.
-------------------------------
lash: The BusyBox LAme SHell (command interpreter)
This command does not yet have proper documentation.
Use lash just as you would use any other shell. It properly handles pipes, redirects, job control, can be used as the shell for scripts, and has a sufficient set of builtins to do what is needed. It does not (yet) support Bourne Shell syntax. If you need things like ``if-then-else'', ``while'', and such use ash or bash. If you just need a very simple and extremely small shell, this will do the job.
-------------------------------
Prints out the length of the specified STRING.
Example:
$ length Hello
5
-------------------------------
Create a link named LINK_NAME or DIRECTORY to the specified TARGET
You may use '--' to indicate that all following arguments are non-options.
Options:
-s make symbolic links instead of hard links
-f remove existing destination files
-n no dereference symlinks - treat like normal file
Example:
$ ln -s BusyBox /tmp/ls
$ ls -l /tmp/ls
lrwxrwxrwx 1 root root 7 Apr 12 18:39 ls -> BusyBox*
-------------------------------
Loads an acm from standard input.
Example:
$ loadacm < /etc/i18n/acmname
-------------------------------
Loads a console font from standard input.
Example:
$ loadfont < /etc/i18n/fontname
-------------------------------
Loads a binary keyboard translation table from standard input.
Example:
$ loadkmap < /etc/i18n/lang-keymap
-------------------------------
Write MESSAGE to the system log. If MESSAGE is omitted, log stdin.
Options:
-s Log to stderr as well as the system log.
-t Log using the specified tag (defaults to user name).
-p Enter the message with the specified priority.
This may be numerical or a ``facility.level'' pair.
Example:
$ logger "hello"
-------------------------------
Print the name of the current user.
Example:
$ logname
root
-------------------------------
Shows the messages from syslogd (using circular buffer).
-------------------------------
Associate LOOPDEVICE with FILE.
Options:
-d Disassociate LOOPDEVICE.
-o OFFSET Start OFFSET bytes into FILE.
-------------------------------
List directory contents
Options:
-1 list files in a single column
-A do not list implied . and ..
-a do not hide entries starting with .
-C list entries by columns
-c with -l: show ctime
-d list directory entries instead of contents
-e list both full date and full time
-F append indicator (one of */=@|) to entries
-i list the i-node for each file
-l use a long listing format
-n list numeric UIDs and GIDs instead of names
-p append indicator (one of /=@|) to entries
-L list entries pointed to by symbolic links
-R list subdirectories recursively
-r sort the listing in reverse order
-S sort the listing by file size
-s list the size of each file, in blocks
-T NUM assume Tabstop every NUM columns
-t with -l: show modification time
-u with -l: show access time
-v sort the listing by version
-w NUM assume the terminal is NUM columns wide
-x list entries by lines instead of by columns
-X sort the listing by extension
-h print sizes in human readable format (e.g., 1K 243M 2G )
-k print sizes in kilobytes(default)
-------------------------------
List the currently loaded kernel modules.
-------------------------------
Creates a range of block or character special files
TYPEs include:
b: Make a block (buffered) device.
c or u: Make a character (un-buffered) device.
p: Make a named pipe. MAJOR and MINOR are ignored for named pipes.
FIRST specifies the number appended to NAME to create the first device. LAST specifies the number of the last item that should be created. If 's' is the last argument, the base device is created as well.
For example:
makedevs /dev/ttyS c 4 66 2 63 -> ttyS2-ttyS63
makedevs /dev/hda b 3 0 0 8 s -> hda,hda1-hda8
Example:
$ makedevs /dev/ttyS c 4 66 2 63
[creates ttyS2-ttyS63]
$ makedevs /dev/hda b 3 0 0 8 s
[creates hda,hda1-hda8]
-------------------------------
Print or check MD5 checksums.
Options: With no FILE, or when FILE is -, read standard input.
-b read files in binary mode
-c check MD5 sums against given list
-t read files in text mode (default)
-g read a string
The following two options are useful only when verifying checksums:
-s don't output anything, status code shows success
-w warn about improperly formated MD5 checksum lines
Example:
$ md5sum < busybox
6fd11e98b98a58f64ff3398d7b324003
$ md5sum busybox
6fd11e98b98a58f64ff3398d7b324003 busybox
$ md5sum -c -
6fd11e98b98a58f64ff3398d7b324003 busybox
busybox: OK
^D
-------------------------------
Create the DIRECTORY(ies) if they do not already exist
Options:
-m set permission mode (as in chmod), not rwxrwxrwx - umask
-p no error if existing, make parent directories as needed
Example:
$ mkdir /tmp/foo
$ mkdir /tmp/foo
/tmp/foo: File exists
$ mkdir /tmp/foo/bar/baz
/tmp/foo/bar/baz: No such file or directory
$ mkdir -p /tmp/foo/bar/baz
-------------------------------
Creates a named pipe (identical to 'mknod name p')
Options:
-m create the pipe using the specified mode (default a=rw)
-------------------------------
Make a MINIX filesystem.
Options:
-c Check the device for bad blocks
-n [14|30] Specify the maximum length of filenames
-i INODES Specify the number of inodes for the filesystem
-l FILENAME Read the bad blocks list from FILENAME
-v Make a Minix version 2 filesystem
-------------------------------
Create a special file (block, character, or pipe).
Options:
-m create the special file using the specified mode (default a=rw)
TYPEs include:
b: Make a block (buffered) device.
c or u: Make a character (un-buffered) device.
p: Make a named pipe. MAJOR and MINOR are ignored for named pipes.
Example:
$ mknod /dev/fd0 b 2 0
$ mknod -m 644 /tmp/pipe p
-------------------------------
Prepare a disk partition to be used as a swap partition.
Options:
-c Check for read-ability.
-v0 Make version 0 swap [max 128 Megs].
-v1 Make version 1 swap [big!] (default for kernels >
2.1.117).
block-count Number of block to use (default is entire partition).
-------------------------------
Creates a temporary file with its name based on TEMPLATE. TEMPLATE is any name with six `Xs' (i.e., /tmp/temp.XXXXXX).
Example:
$ mktemp /tmp/temp.XXXXXX
/tmp/temp.mWiLjM
$ ls -la /tmp/temp.mWiLjM
-rw------- 1 andersen andersen 0 Apr 25 17:10 /tmp/temp.mWiLjM
-------------------------------
Used for hight level module loading and unloading.
Example:
$ modprobe cdrom
-------------------------------
More is a filter for viewing FILE one screenful at a time.
Example:
$ dmesg | more
-------------------------------
Mount a filesystem
Flags:
-a: Mount all filesystems in fstab.
-f: "Fake" Add entry to mount table but don't mount it.
-n: Don't write a mount table entry.
-o option: One of many filesystem options, listed below.
-r: Mount the filesystem read-only.
-t fs-type: Specify the filesystem type.
-w: Mount for reading and writing (default).
Options for use with the ``-o'' flag:
async/sync: Writes are asynchronous / synchronous.
atime/noatime: Enable / disable updates to inode access times.
dev/nodev: Allow use of special device files / disallow them.
exec/noexec: Allow use of executable files / disallow them.
loop: Mounts a file via loop device.
suid/nosuid: Allow set-user-id-root programs / disallow them.
remount: Re-mount a mounted filesystem, changing its flags.
ro/rw: Mount for read-only / read-write.
bind: Use the linux 2.4.x "bind" feature.
There are EVEN MORE flags that are specific to each filesystem. You'll have to see the written documentation for those filesystems.
Example:
$ mount
/dev/hda3 on / type minix (rw)
proc on /proc type proc (rw)
devpts on /dev/pts type devpts (rw)
$ mount /dev/fd0 /mnt -t msdos -o ro
$ mount /tmp/diskimage /opt -t ext2 -o loop
-------------------------------
Control magnetic tape drive operation
Available Opcodes:
bsf bsfm bsr bss datacompression drvbuffer eof eom erase fsf fsfm fsr fss load lock mkpart nop offline ras1 ras2 ras3 reset retension rew rewoffline seek setblk setdensity setpart tell unload unlock weof wset
-------------------------------
Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY.
Example:
$ mv /tmp/foo /bin/bar
-------------------------------
Netcat opens a pipe to IP:port
Options:
-l listen mode, for inbound connects
-p PORT local port number
-e PROG program to exec after connect (dangerous!)
Example:
$ nc foobar.somedomain.com 25
220 foobar ESMTP Exim 3.12 #1 Sat, 15 Apr 2000 00:03:02 -0600
help
214-Commands supported:
214- HELO EHLO MAIL RCPT DATA AUTH
214 NOOP QUIT RSET HELP
quit
221 foobar closing connection
-------------------------------
Queries the nameserver for the IP address of the given HOST optionally using a specified DNS server
Example:
$ nslookup localhost
Server: default
Address: default
Name: debian
Address: 127.0.0.1
-------------------------------
Lists the PIDs of all processes with names that match the names on the command line
Example:
$ pidof init
1
-------------------------------
Send ICMP ECHO_REQUEST packets to network hosts.
Options:
-c COUNT Send only COUNT pings.
-s SIZE Send SIZE data bytes in packets (default=56).
-q Quiet mode, only displays output at start
and when finished.
Example:
$ ping localhost
PING slag (127.0.0.1): 56 data bytes
64 bytes from 127.0.0.1: icmp_seq=0 ttl=255 time=20.1 ms
--- debian ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 20.1/20.1/20.1 ms
-------------------------------
Move the current root file system to PUT_OLD and make NEW_ROOT the new root file system.
-------------------------------
Halt the system and request that the kernel shut off the power.
-------------------------------
Formats and prints ARGUMENT(s) according to FORMAT,
Where FORMAT controls the output exactly as in C printf.
Example:
$ printf "Val=%d\n" 5
Val=5
-------------------------------
Report process status
This version of ps accepts no options.
Example:
$ ps
PID Uid Gid State Command
1 root root S init
2 root root S [kflushd]
3 root root S [kupdate]
4 root root S [kpiod]
5 root root S [kswapd]
742 andersen andersen S [bash]
743 andersen andersen S -bash
745 root root S [getty]
2990 andersen andersen R ps
-------------------------------
Print the full filename of the current working directory.
Example:
$ pwd
/root
-------------------------------
Get and possibly set the system date and time from a remote HOST.
Options:
-s Set the system date and time (default).
-p Print the date and time.
-------------------------------
Read a symbolic link.
-------------------------------
Reboot the system.
-------------------------------
Changes priority of running processes. Allowed priorities range from 20 (the process runs only when nothing else is running) to 0 (default priority) to -20 (almost nothing else ever gets to run).
-------------------------------
Resets the screen.
-------------------------------
Remove (unlink) the FILE(s). You may use '--' to indicate that all following arguments are non-options.
Options:
-i always prompt before removing each destination -f remove existing destinations, never prompt
-r or -R remove the contents of directories recursively
Example:
$ rm -rf /tmp/foo
-------------------------------
Remove the DIRECTORY(ies), if they are empty.
Example:
# rmdir /tmp/foo
-------------------------------
Unloads the specified kernel modules from the kernel.
Options:
-a Try to remove all unused kernel modules.
Example:
$ rmmod tulip
-------------------------------
Edit the kernel's routing tables
-------------------------------
Outputs a cpio archive of the rpm file.
-------------------------------
Options:
-n suppress automatic printing of pattern space
-e script add the script to the commands to be executed
-f scriptfile add the contents of script-file to the commands to be executed
If no -e or -f is given, the first non-option argument is taken as the sed script to interpret. All remaining arguments are names of input files; if no input files are specified, then the standard input is read.
Example:
$ echo "foo" | sed -e 's/f[a-zA-Z]o/bar/g'
bar
-------------------------------
Set entries into the kernel's scancode-to-keycode map, allowing unusual keyboards to generate usable keycodes.
SCANCODE may be either xx or e0xx (hexadecimal), and KEYCODE is given in decimal
Example:
$ setkeycodes e030 127
-------------------------------
Pause for N seconds.
Example:
$ sleep 2
[2 second delay results]
-------------------------------
Sorts lines of text in the specified files
Options:
-u suppress duplicate lines
-r sort in reverse order
-n sort numerics
Example:
$ echo -e "e\nf\nb\nd\nc\na" | sort
a
b
c
d
e
f
-------------------------------
Without arguments, prints baud rate, line discipline, and deviations from stty sane.
Options:
-F DEVICE open device instead of stdin
-a print all current settings in human-readable form
-g print in stty-readable form
[SETTING] see manpage
-------------------------------
Stop swapping virtual memory pages on DEVICE.
Options:
-a Stop swapping on all swap devices
-------------------------------
Start swapping virtual memory pages on DEVICE.
Options:
-a Start swapping on all swap devices
-------------------------------
Write all buffered filesystem blocks to disk.
-------------------------------
Linux system and kernel logging utility. Note that this version of syslogd ignores /etc/syslog.conf.
Options:
-m NUM Interval between MARK lines (default=20min, 0=off)
-n Run as a foreground process
-O FILE Use an alternate log file (default=/var/log/messages)
-R HOST[:PORT] Log to IP or hostname on PORT (default PORT=514/UDP)
-L Log locally and via network logging (default is network only)
Example:
$ syslogd -R masterlog:514
$ syslogd -R 192.168.1.1:601
-------------------------------
Print last 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:
-c N[kbm] output the last N bytes
-n N[kbm] print last N lines instead of last 10
-f output data as the file grows
-q never output headers giving file names
-s SEC wait SEC seconds between reads with -f
-v always output headers giving file names
If the first character of N (bytes or lines) is a '+', output begins with the Nth item from the start of each file, otherwise, print the last N items in the file. N bytes may be suffixed by k (x1024), b (x512), or m (1024^2).
Example:
$ tail -n 1 /etc/resolv.conf
nameserver 10.0.0.1
-------------------------------
Create, extract, or list files from a tar file.
Options:
c create
x extract
t list
File selection:
f name of TARFILE or "-" for stdin
O extract to stdout
exclude file to exclude
X file with names to exclude
C change to directory DIR before operation
v verbosely list files processed
Example:
$ zcat /tmp/tarball.tar.gz | tar -xf -
$ tar -cf /tmp/tarball.tar /usr/local
-------------------------------
Copy standard input to each FILE, and also to standard output.
Options:
-a append to the given FILEs, do not overwrite
Example:
$ echo "Hello" | tee /tmp/foo
$ cat /tmp/foo
Hello
-------------------------------
Telnet is used to establish interactive communication with another computer over a network using the TELNET protocol.
-------------------------------
Checks file types and compares values returning an exit code determined by the value of EXPRESSION.
Example:
$ test 1 -eq 2
$ echo $?
1
$ test 1 -eq 1
$ echo $?
0
$ [ -d /etc ]
$ echo $?
0
$ [ -d /junk ]
$ echo $?
1
-------------------------------
Transfers a file from/to a tftp server using ``octet'' mode.
Options:
-b SIZE Transfer blocks of SIZE octets.
-g Get file.
-l FILE Transfer local FILE.
-p Put file.
-r FILE Transfer remote FILE.
-------------------------------
Runs the program COMMAND with arguments ARGS. When COMMAND finishes,
-------------------------------
Update the last-modified date on the given FILE[s].
Options:
-c Do not create any files
Example:
$ ls -l /tmp/foo
/bin/ls: /tmp/foo: No such file or directory
$ touch /tmp/foo
$ ls -l /tmp/foo
-rw-rw-r-- 1 andersen andersen 0 Apr 15 01:11 /tmp/foo
-------------------------------
Translate, squeeze, and/or delete characters from standard input, writing to standard output.
Options:
-c take complement of STRING1
-d delete input characters coded STRING1
-s squeeze multiple output characters of STRING2 into one character
Example:
$ echo "gdkkn vnqkc" | tr [a-y] [b-z]
hello world
-------------------------------
| traceroute [-dnrv] [-m max_ttl] [-p port#] [-q nqueries] | |
| [-s src_addr] [-t tos] [-w wait] host [data size] |
trace the route ip packets follow going to ``host'' Options:
-d set SO_DEBUG options to socket
-n Print hop addresses numerically rather than symbolically
-r Bypass the normal routing tables and send directly to a host
-v Verbose output
-m max_ttl Set the max time-to-live (max number of hops)
-p port# Set the base UDP port number used in probes
(default is 33434)
-q nqueries Set the number of probes per ``ttl'' to nqueries
(default is 3)
-s src_addr Use the following IP address as the source address
-t tos Set the type-of-service in probe packets to the following value
(default 0)
-w wait Set the time (in seconds) to wait for a response to a probe
(default 3 sec.).
-------------------------------
Return an exit code of TRUE (0).
Example:
$ true
$ echo $?
0
-------------------------------
Print the file name of the terminal connected to standard input.
Options:
-s print nothing, only return an exit status
Example:
$ tty
/dev/tty2
-------------------------------
Unmount file systems
Flags:
-a Unmount all file systems in /etc/mtab
-n Don't erase /etc/mtab entries
-r Try to remount devices as read-only if mount is busy
-f Force umount (i.e., unreachable NFS server)
-l Do not free loop device (if a loop device has been used)
Example:
$ umount /dev/hdc1
-------------------------------
Print certain system information. With no OPTION, same as -s.
Options:
-a print all information
-m the machine (hardware) type
-n print the machine's network node hostname
-r print the operating system release
-s print the operating system name
-p print the host processor type
-v print the operating system version
Example:
$ uname -a
Linux debian 2.2.15pre13 #5 Tue Mar 14 16:03:50 MST 2000 i686 unknown
-------------------------------
Discard all but one of successive identical lines from INPUT (or standard input), writing to OUTPUT (or standard output).
Options:
-c prefix lines by the number of occurrences
-d only print duplicate lines
-u only print unique lines
Example:
$ echo -e "a\na\nb\nc\nc\na" | sort | uniq
a
b
c
-------------------------------
Converts FILE from unix format to dos format. When no option is given, the input is converted to the opposite output format. When no file is given, uses stdin for input and stdout for output. Options:
-u output will be in UNIX format
-d output will be in DOS format
-------------------------------
Periodically flushes filesystem buffers.
Options:
-S force use of sync(2) instead of flushing
-s SECS call sync this often (default 30)
-f SECS flush some buffers this often (default 5)
-------------------------------
Display the time since the last boot.
Example:
$ uptime
1:55pm up 2:30, load average: 0.09, 0.04, 0.00
-------------------------------
Pause for N microseconds.
Example:
$ usleep 1000000
[pauses for 1 second]
-------------------------------
Uudecode a file that is uuencoded.
Options:
-o FILE direct output to FILE
Example:
$ uudecode -o busybox busybox.uu
$ ls -l busybox
-rwxr-xr-x 1 ams ams 245264 Jun 7 21:35 busybox
-------------------------------
Uuencode a file.
Options:
-m use base64 encoding per RFC1521
Example:
$ uuencode busybox busybox
begin 755 busybox
<encoded file snipped>
$ uudecode busybox busybox > busybox.uu
$
-------------------------------
edit FILE.
Options:
-R Read-only- do not write to the file.
-------------------------------
Periodically write to watchdog device DEV
-------------------------------
Print line, word, and byte counts for each FILE, and a total line if more than one FILE is specified. With no FILE, read standard input.
Options:
-c print the byte counts
-l print the newline counts
-L print the length of the longest line
-w print the word counts
Example:
$ wc /etc/passwd
31 46 1365 /etc/passwd
-------------------------------
| wget [-c|--continue] [-q|--quiet] [-O|--output-document file] | |
| [--header 'header: value'] [-P DIR] url |
wget retrieves files via HTTP or FTP
Options:
-c continue retrieval of aborted transfers
-q quiet mode - do not print
-P Set directory prefix to DIR
-O save to filename ('-' for stdout)
-------------------------------
Locates a COMMAND.
Example:
$ which login
/bin/login
-------------------------------
Prints the user name associated with the current effective user id.
-------------------------------
Executes COMMAND on every item given by standard input.
Example:
$ ls | xargs gzip
$ find . -name '*.c' -print | xargs rm
-------------------------------
Repeatedly outputs a line with all specified STRING(s), or 'y'.
-------------------------------
Uncompress to stdout.
-------------------------------
GNU Libc uses the Name Service Switch (NSS) to configure the behavior of the C library for the local environment, and to configure how it reads system data, such as passwords and group information. BusyBox has made it Policy that it will never use NSS, and will never use and libc calls that make use of NSS. This allows you to run an embedded system without the need for installing an /etc/nsswitch.conf file and without and /lib/libnss_* libraries installed.
If you are using a system that is using a remote LDAP server for authentication via GNU libc NSS, and you want to use BusyBox, then you will need to adjust the BusyBox source. Chances are though, that if you have enough space to install of that stuff on your system, then you probably want the full GNU utilities.
textutils(1), shellutils(1), etc...
Erik Andersen <andersee@debian.org> <andersen@codepoet.org>
The following people have contributed code to BusyBox whether they know it or not.
Erik Andersen <andersee@debian.org> <andersen@codepoet.org>
Tons of new stuff, major rewrite of most of the
core apps, tons of new apps as noted in header files.
John Beppu <beppu@codepoet.org>
du, head, nslookup, sort, tee, uniq (so Kraai could rewrite them ;-),
documentation
Edward Betts <edward@debian.org>
expr, hostid, logname, tty, wc, whoami, yes
=for html <br>
Brian Candler <B.Candler@pobox.com>
tiny-ls(ls)
Randolph Chung <tausq@debian.org>
fbset, ping, hostname, and mkfifo
Dave Cinege <dcinege@psychosis.com>
more(v2), makedevs, dutmp, modularization, auto links file,
various fixes, Linux Router Project maintenance
Larry Doolittle <ldoolitt@recycle.lbl.gov>
various fixes, shell rewrite
Karl M. Hegbloom <karlheg@debian.org>
cp_mv.c, the test suite, various fixes to utility.c, &c.
Sterling Huxley <sterling@europa.com>
vi (!!!)
Daniel Jacobowitz <dan@debian.org>
mktemp.c
Matt Kraai <kraai@alumni.carnegiemellon.edu>
documentation, bugfixes
John Lombardo <john@deltanet.com>
dirname, tr
Glenn McGrath <bug1@netconnect.com.au>
ar.c
Vladimir Oleynik <dzo@simtreas.ru>
cmdedit, stty-port, locale, various fixes
and irreconcilable critic of everything not perfect.
Bruce Perens <bruce@pixar.com>
Original author of BusyBox. His code is still in many apps.
Chip Rosenthal <chip@unicom.com>, <crosenth@covad.com>
wget - Contributed by permission of Covad Communications
Pavel Roskin <proski@gnu.org>
Lots of bugs fixes and patches.
Gyepi Sam <gyepi@praxis-sw.com>
Remote logging feature for syslogd
Linus Torvalds <torvalds@transmeta.com>
mkswap, fsck.minix, mkfs.minix
Mark Whitley <markw@codepoet.org>
sed remix, bug fixes, style-guide, etc.
Charles P. Wright <cpwright@villagenet.com>
gzip, mini-netcat(nc)
Enrique Zanardi <ezanardi@ull.es>
tarcat (since removed), loadkmap, various fixes, Debian maintenance