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:
[, ash, basename, busybox, cal, cat, chgrp, chmod, chown, chroot,
clear, cp, cut, date, dc, dd, df, dirname, dmesg, du, echo, env,
false, fgrep, find, free, getty, grep, gunzip, gzip, halt, head,
hexdump, hostname, id, ifconfig, init, insmod, kill, killall,
klogd, ln, logger, login, ls, lsmod, mesg, mkdir, mknod, more,
mount, mv, nslookup, openvt, passwd, ping, poweroff, ps, pwd,
reboot, reset, rm, rmdir, rmmod, route, sed, sh, sleep, sort, su,
sulogin, sync, syslogd, tail, tar, test, top, touch, true, tty,
udhcpc, umount, uname, uniq, uptime, which, whoami, yes, zcat
-------------------------------
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
-------------------------------
Display a calendar.
Options:
-j Use julian dates.
-y Display the entire year.
-------------------------------
Concatenates FILE(s) and prints them to stdout.
Options:
-u ignored since unbuffered i/o is always used
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*
-------------------------------
Clear screen.
-------------------------------
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
-------------------------------
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 + /' -> 16p - Prints the value on the top of the stack, without altering the stack. f - Prints the entire contents of the stack without altering anything. o - Pops the value off the top of the stack and uses it to set the output radix.
Only 10 and 16 are supported.
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
-------------------------------
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
-------------------------------
Summarizes disk space used for each FILE and/or directory. Disk space is printed in units of 1024 bytes.
Options:
-a show sizes of files in addition to directories
-H follow symbolic links that are FILE command line args
-L follow all symbolic links encountered
-d N limit output to directories (and files with -a) of depth < N
-c output a grand total
-l count sizes many times if hard linked
-s display only a total for each argument
-x skip directories on different filesystems
-h print sizes in human readable format (e.g., 1K 243M 2G )
-m print sizes in megabytes
-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 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
-------------------------------
Return an exit code of FALSE (1).
Example:
$ false
$ echo $?
1
-------------------------------
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
-inum N File has inode number N
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
-------------------------------
Opens a tty, prompts for a login name, then invokes /bin/login
Options:
-h Enable hardware (RTS/CTS) flow control.
-i Do not display /etc/issue before running login.
-L Local line, so do not do carrier detect.
-m Get baud rate from modem's CONNECT status message.
-w Wait for a CR or LF before sending /etc/issue.
-n Do not prompt the user for a login name.
-f issue_file Display issue_file instead of /etc/issue.
-l login_app Invoke login_app instead of /bin/login.
-t timeout Terminate after timeout if no username is read.
-I initstring Sets the init string to send before anything else.
-H login_host Log login_host into the utmp file as the hostname.
-------------------------------
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(s) with maximum compression.
When FILE is '-' or unspecified, 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
-c NUM output the first NUM bytes
-q never output headers giving file names
-v always output headers giving file names
Example:
$ head -n 2 /etc/passwd
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
-------------------------------
The hexdump utility is a filter which displays the specified files, or the standard input, if no files are specified, in a user specified format
-b One-byte octal display
-c One-byte character display
-d Two-byte decimal display
-e FORMAT STRING
-f FORMAT FILE
-n LENGTH Interpret only length bytes of input
-o Two-byte octal display
-s OFFSET Skip offset byte
-v display all input data
-x Two-byte hexadecimal display
-------------------------------
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 Fully qualified domain name
-F 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
-c prints only the security context
", B<-n> print a name instead of a number (with for B<-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: [add <address>[/<prefixlen>]] [del <address>[/<prefixlen>]]
[[-]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 order 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 tty4
tty5::respawn:/sbin/getty 38400 tty5
# 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
-m Output load map to stdout -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:
-c n Sets the default log level of console messages to n.
-n Run as a foreground process.
-------------------------------
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*
-------------------------------
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"
-------------------------------
Begin a new session on the system
Options:
-f Do not authenticate (user already authenticated)
-h Name of the remote host for this login.
-p Preserve environment.
-------------------------------
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 )
USAGE_SELINUX(" -k print security context
-K print security context in long format
", )
-------------------------------
List the currently loaded kernel modules.
-------------------------------
mesg [Y|N], controls write access to your terminal
y Allow write access to your terminal.
n Disallow write access to your terminal.
-------------------------------
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
-------------------------------
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
-------------------------------
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
-------------------------------
Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY.
Example:
$ mv /tmp/foo /bin/bar
-------------------------------
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
-------------------------------
Start a command on a new virtual terminal
Example:
openvt 2 /bin/ash
-------------------------------
Change a user password. If no name is specified, changes the password for the current user. Options:
-a Define which algorithm shall be used for the password.
(Choices: des, md5 PASSWORD_ALG_TYPES(", sha1") )
-d Delete the password for the specified user account.
-l Locks (disables) the specified user account.
-u Unlocks (re-enables) the specified user account.
-------------------------------
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
-------------------------------
Halt the system and request that the kernel shut off the power.
-------------------------------
Report process status
Options:
-c show SE Linux context", "
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
-------------------------------
Reboot the system.
-------------------------------
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 Remove all unused modules (recursively)
Example:
$ rmmod tulip
-------------------------------
Edit the kernel's routing tables.
Options:
-n Dont resolve names.
-e Display other/more information
-------------------------------
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
-------------------------------
Pause for a time equal to the total of the args given, where each arg can
have an optional suffix of (s)econds, (m)inutes, (h)ours, or (d)ays.
Example:
$ sleep 2
[2 second delay results]
$ sleep 1d 3h 22m 8s
[98528 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
-------------------------------
Change user id or become root. Options:
-p Preserve environment
-------------------------------
Single user login Options:
-f Do not authenticate (user already authenticated)
-h Name of the remote host for this login.
-p Preserve environment.
-------------------------------
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)
-C Log to a circular buffer (read the buffer using logread)
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
Archive format selection:
z Filter the archive through gzip
j Filter the archive through bzip2
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
-------------------------------
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
-------------------------------
top provides an view of processor activity in real time. This utility reads the status for all processes in /proc each <seconds> and shows the status for however many processes will fit on the screen. This utility will not show processes that are started after program startup, but it will show the EXIT status for and PIDs that exit while it is running.
-------------------------------
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
-------------------------------
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
-------------------------------
-c, --clientid=CLIENTID Client identifier
-H, --hostname=HOSTNAME Client hostname
-h, Alias for -H
-f, --foreground Do not fork after getting lease
-b, --background Fork to background if lease cannot be immediately negotiated.
-i, --interface=INTERFACE Interface to use (default: eth0)
-n, --now Exit with failure if lease cannot be immediately negotiated.
-p, --pidfile=file Store process ID of daemon in file
-q, --quit Quit after obtaining lease
-r, --request=IP IP address to request (default: none)
-s, --script=file Run file at dhcp events (default: /usr/share/udhcpc/default.script)
-v, --version Display version
-------------------------------
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
-f N skip the first N fields
-s N skip the first N chars (after any skipped fields)
Example:
$ echo -e "a\na\nb\nc\nc\na" | sort | uniq
a
b
c
-------------------------------
Display the time since the last boot.
Example:
$ uptime
1:55pm up 2:30, load average: 0.09, 0.04, 0.00
-------------------------------
Locates a COMMAND.
Example:
$ which login
/bin/login
-------------------------------
Prints the user name associated with the current effective user id.
-------------------------------
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 <andersen@codepoet.org>
The following people have contributed code to BusyBox whether they know it or not.
Erik Andersen <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, xargs(current), httpd(current);
ports: ash, crond, fdisk, inetd, stty, traceroute, top;
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
Glenn Engel <glenne@engel.org>
httpd