1Please see the LICENSE file for details on copying and usage.
2Please refer to the INSTALL file for instructions on how to build.
3
4What is busybox:
5
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.
14
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.
23
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).
31
32----------------
33
34Using busybox:
35
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.)
40
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").
45
46 The "standalone shell" mode is an easy way to try out busybox; this is a
47 command shell that calls the builtin 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.)
50
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").
57
58----------------
59
60Downloading the current source code:
61
62 Source for the latest released version, as well as daily snapshots, can always
63 be downloaded from
64
65 http://busybox.net/downloads/
66
67 You can browse the up to the minute source code and change history online.
68
69 http://www.busybox.net/cgi-bin/viewcvs.cgi/trunk/busybox/
70
71 Anonymous SVN access is available. For instructions, check out:
72
73 http://busybox.net/subversion.html
74
75 For those that are actively contributing and would like to check files in,
76 see:
77
78 http://busybox.net/developer.html
79
80 The developers also have a bug and patch tracking system
81 (http://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 subversion changelog.
84
85----------------
86
87getting help:
88
89 when you find you need help, you can check out the busybox mailing list
90 archives at http://busybox.net/lists/busybox/ or even join
91 the mailing list if you are interested.
92
93----------------
94
95bugs:
96
97 if you find bugs, please submit a detailed bug report to the busybox mailing
98 list at busybox@busybox.net. a well-written bug report should include a
99 transcript of a shell session that demonstrates the bad behavior and enables
100 anyone else to duplicate the bug on their own machine. the following is such
101 an example:
102
103 to: busybox@busybox.net
104 from: diligent@testing.linux.org
105 subject: /bin/date doesn't work
106
107 package: busybox
108 version: 1.00
109
110 when i execute busybox 'date' it produces unexpected results.
111 with gnu date i get the following output:
112
113 $ date
114 fri oct 8 14:19:41 mdt 2004
115
116 but when i use busybox date i get this instead:
117
118 $ date
119 illegal instruction
120
121 i am using debian unstable, kernel version 2.4.25-vrs2 on a netwinder,
122 and the latest uclibc from cvs. thanks for the wonderful program!
123
124 -diligent
125
126 note the careful description and use of examples showing not only what
127 busybox does, but also a counter example showing what an equivalent app
128 does (or pointing to the text of a relevant standard). Bug reports lacking
129 such detail may never be fixed... Thanks for understanding.
130
131----------------
132
133Portability:
134
135 Busybox is developed and tested on Linux 2.4 and 2.6 kernels, compiled
136 with gcc (the unit-at-a-time optimizations in version 3.4 and later are
137 worth upgrading to get, but older versions should work), and linked against
138 uClibc (0.9.27 or greater) or glibc (2.2 or greater). In such an
139 environment, the full set of busybox features should work, and if
140 anything doesn't we want to know about it so we can fix it.
141
142 There are many other environments out there, in which busybox may build
143 and run just fine. We just don't test them. Since busybox consists of a
144 large number of more or less independent applets, portability is a question
145 of which features work where. Some busybox applets (such as cat and rm) are
146 highly portable and likely to work just about anywhere, while others (such as
147 insmod and losetup) require recent Linux kernels with recent C libraries.
148
149 Earlier versions of Linux and glibc may or may not work, for any given
150 configuration. Linux 2.2 or earlier should mostly work (there's still
151 some support code in things like mount.c) but this is no longer regularly
152 tested, and inherently won't support certain features (such as long files
153 and --bind mounts). The same is true for glibc 2.0 and 2.1: expect a higher
154 testing and debugging burden using such old infrastructure. (The busybox
155 developers are not very interested in supporting these older versions, but
156 will probably accept small self-contained patches to fix simple problems.)
157
158 Some environments are not recommended. Early versions of uClibc were buggy
159 and missing many features: upgrade. Linking against libc5 or dietlibc is
160 not supported and not interesting to the busybox developers. (The first is
161 obsolete and has no known size or feature advantages over uClibc, the second
162 has known bugs that its developers have actively refused to fix.) Ancient
163 Linux kernels (2.0.x and earlier) are similarly uninteresting.
164
165 In theory it's possible to use Busybox under other operating systems (such as
166 MacOS X, Solaris, Cygwin, or the BSD Fork Du Jour). This generally involves
167 a different kernel and a different C library at the same time. While it
168 should be possible to port the majority of the code to work in one of
169 these environments, don't be suprised if it doesn't work out of the box. If
170 you're into that sort of thing, start small (selecting just a few applets)
171 and work your way up.
172
173 Shaun Jackman has recently (2005) ported busybox to a combination of newlib
174 and libgloss, and some of his patches have been integrated. This platform
175 may join glibc/uclibc and Linux as a supported combination with the 1.1
176 release, but is not supported in 1.0.
177
178Supported hardware:
179
180 BusyBox in general will build on any architecture supported by gcc. We
181 support both 32 and 64 bit platforms, and both big and little endian
182 systems.
183
184 Under 2.4 Linux kernels, kernel module loading was implemented in a
185 platform-specific manner. Busybox's insmod utility has been reported to
186 work under ARM, CRIS, H8/300, x86, ia64, x86_64, m68k, MIPS, PowerPC, S390,
187 SH3/4/5, Sparc, v850e, and x86_64. Anything else probably won't work.
188
189 The module loading mechanism for the 2.6 kernel is much more generic, and
190 we believe 2.6.x kernel module loading support should work on all
191 architectures supported by the kernel.
192
193----------------
194
195Please feed suggestions, bug reports, insults, and bribes back to the busybox
196maintainer:
197 Denis Vlasenko
198 <vda.linux@googlemail.com>
199