1Please see the LICENSE file for details on copying and usage.
2Please refer to the INSTALL file for instructions on how to build.
4What is busybox:
6 BusyBox combines tiny versions of many common UNIX utilities into a single
7 small executable. It provides minimalist replacements for most of the
8 utilities you usually find in bzip2, coreutils, dhcp, diffutils, e2fsprogs,
9 file, findutils, gawk, grep, inetutils, less, modutils, net-tools, procps,
10 sed, shadow, sysklogd, sysvinit, tar, util-linux, and vim. The utilities
11 in BusyBox often have fewer options than their full-featured cousins;
12 however, the options that are included provide the expected functionality
13 and behave very much like their larger counterparts.
15 BusyBox has been written with size-optimization and limited resources in
16 mind, both to produce small binaries and to reduce run-time memory usage.
17 Busybox is also extremely modular so you can easily include or exclude
18 commands (or features) at compile time. This makes it easy to customize
19 embedded systems; to create a working system, just add /dev, /etc, and a
20 Linux kernel. Busybox (usually together with uClibc) has also been used as
21 a component of "thin client" desktop systems, live-CD distributions, rescue
22 disks, installers, and so on.
24 BusyBox provides a fairly complete POSIX environment for any small system,
25 both embedded environments and more full featured systems concerned about
26 space. Busybox is slowly working towards implementing the full Single Unix
27 Specification V3 (http://www.opengroup.org/onlinepubs/009695399/), but isn't
28 there yet (and for size reasons will probably support at most UTF-8 for
29 internationalization). We are also interested in passing the Linux Test
30 Project (http://ltp.sourceforge.net).
36 BusyBox is extremely configurable. This allows you to include only the
37 components and options you need, thereby reducing binary size. Run 'make
38 config' or 'make menuconfig' to select the functionality that you wish to
39 enable. (See 'make help' for more commands.)
41 The behavior of busybox is determined by the name it's called under: as
42 "cp" it behaves like cp, as "sed" it behaves like sed, and so on. Called
43 as "busybox" it takes the second argument as the name of the applet to
44 run (I.E. "./busybox ls -l /proc").
46 The "standalone shell" mode is an easy way to try out busybox; this is a
47 command shell that calls the built-in applets without needing them to be
48 installed in the path. (Note that this requires /proc to be mounted, if
49 testing from a boot floppy or in a chroot environment.)
51 The build automatically generates a file "busybox.links", which is used by
52 'make install' to create symlinks to the BusyBox binary for all compiled in
53 commands. This uses the CONFIG_PREFIX environment variable to specify
54 where to install, and installs hardlinks or symlinks depending
55 on the configuration preferences. (You can also manually run
56 the install script at "applets/install.sh").
60Downloading the current source code:
62 Source for the latest released version, as well as daily snapshots, can always
63 be downloaded from
67 You can browse the up to the minute source code and change history online.
71 Anonymous GIT access is available. For instructions, check out:
75 For those that are actively contributing and would like to check files in,
80 The developers also have a bug and patch tracking system
81 (https://bugs.busybox.net) although posting a bug/patch to the mailing list
82 is generally a faster way of getting it fixed, and the complete archive of
83 what happened is the git changelog.
85 Note: if you want to compile busybox in a busybox environment you must
86 select CONFIG_DESKTOP.
92 when you find you need help, you can check out the busybox mailing list
93 archives at http://busybox.net/lists/busybox/ or even join
94 the mailing list if you are interested.
100 if you find bugs, please submit a detailed bug report to the busybox mailing
101 list at firstname.lastname@example.org. a well-written bug report should include a
102 transcript of a shell session that demonstrates the bad behavior and enables
103 anyone else to duplicate the bug on their own machine. the following is such
104 an example:
106 to: email@example.com
107 from: firstname.lastname@example.org
108 subject: /bin/date doesn't work
110 package: busybox
111 version: 1.00
113 when i execute busybox 'date' it produces unexpected results.
114 with gnu date i get the following output:
116 $ date
117 fri oct 8 14:19:41 mdt 2004
119 but when i use busybox date i get this instead:
121 $ date
122 illegal instruction
124 i am using debian unstable, kernel version 2.4.25-vrs2 on a netwinder,
125 and the latest uclibc from cvs.
129 note the careful description and use of examples showing not only what
130 busybox does, but also a counter example showing what an equivalent app
131 does (or pointing to the text of a relevant standard). Bug reports lacking
132 such detail may never be fixed... Thanks for understanding.
138 Busybox is developed and tested on Linux 2.4 and 2.6 kernels, compiled
139 with gcc (the unit-at-a-time optimizations in version 3.4 and later are
140 worth upgrading to get, but older versions should work), and linked against
141 uClibc (0.9.27 or greater) or glibc (2.2 or greater). In such an
142 environment, the full set of busybox features should work, and if
143 anything doesn't we want to know about it so we can fix it.
145 There are many other environments out there, in which busybox may build
146 and run just fine. We just don't test them. Since busybox consists of a
147 large number of more or less independent applets, portability is a question
148 of which features work where. Some busybox applets (such as cat and rm) are
149 highly portable and likely to work just about anywhere, while others (such as
150 insmod and losetup) require recent Linux kernels with recent C libraries.
152 Earlier versions of Linux and glibc may or may not work, for any given
153 configuration. Linux 2.2 or earlier should mostly work (there's still
154 some support code in things like mount.c) but this is no longer regularly
155 tested, and inherently won't support certain features (such as long files
156 and --bind mounts). The same is true for glibc 2.0 and 2.1: expect a higher
157 testing and debugging burden using such old infrastructure. (The busybox
158 developers are not very interested in supporting these older versions, but
159 will probably accept small self-contained patches to fix simple problems.)
161 Some environments are not recommended. Early versions of uClibc were buggy
162 and missing many features: upgrade. Linking against libc5 or dietlibc is
163 not supported and not interesting to the busybox developers. (The first is
164 obsolete and has no known size or feature advantages over uClibc, the second
165 has known bugs that its developers have actively refused to fix.) Ancient
166 Linux kernels (2.0.x and earlier) are similarly uninteresting.
168 In theory it's possible to use Busybox under other operating systems (such as
169 MacOS X, Solaris, Cygwin, or the BSD Fork Du Jour). This generally involves
170 a different kernel and a different C library at the same time. While it
171 should be possible to port the majority of the code to work in one of
172 these environments, don't be surprised if it doesn't work out of the box. If
173 you're into that sort of thing, start small (selecting just a few applets)
174 and work your way up.
176 In 2005 Shaun Jackman has ported busybox to a combination of newlib
177 and libgloss, and some of his patches have been integrated.
181 BusyBox in general will build on any architecture supported by gcc. We
182 support both 32 and 64 bit platforms, and both big and little endian
185 Under 2.4 Linux kernels, kernel module loading was implemented in a
186 platform-specific manner. Busybox's insmod utility has been reported to
187 work under ARM, CRIS, H8/300, x86, ia64, x86_64, m68k, MIPS, PowerPC, S390,
188 SH3/4/5, Sparc, and v850e. Anything else probably won't work.
190 The module loading mechanism for the 2.6 kernel is much more generic, and
191 we believe 2.6.x kernel module loading support should work on all
192 architectures supported by the kernel.
196Please feed suggestions, bug reports, insults, and bribes back to the busybox
203 Denys Vlasenko