4 The BusyBox build process is similar to the Linux kernel build:
6 make menuconfig # This creates a file called ".config"
7 make # This creates the "busybox" executable
8 make install # or make CONFIG_PREFIX=/path/from/root install
10 The full list of configuration and install options is available by typing:
17 The easy way to try out BusyBox for the first time, without having to install
18 it, is to enable all features and then use "standalone shell" mode with a
21 To enable all features, use "make defconfig", which produces the largest
22 general-purpose configuration. It's allyesconfig minus debugging options,
23 optional packaging choices, and a few special-purpose features requiring
24 extra configuration to use. Then enable "standalone shell" feature:
28 # select Busybox Settings
29 # then General Configuration
30 # then exec prefers applets
31 # exit back to top level menu
33 # then Standalone shell
34 # exit back to top level menu
35 # exit and save new configuration
37 # use these commands to modify .config directly:
38 sed -e 's/.*FEATURE_PREFER_APPLETS.*/CONFIG_FEATURE_PREFER_APPLETS=y/' -i .config
39 sed -e 's/.*FEATURE_SH_STANDALONE.*/CONFIG_FEATURE_SH_STANDALONE=y/' -i .config
43 Standalone shell mode causes busybox's built-in command shell to run
44 any built-in busybox applets directly, without looking for external
45 programs by that name. Supplying an empty command path (as above) means
46 the only commands busybox can find are the built-in ones.
48 Note that the standalone shell requires CONFIG_BUSYBOX_EXEC_PATH
49 to be set appropriately, depending on whether or not /proc/self/exe is
50 available or not. If you do not have /proc, then point that config option
51 to the location of your busybox binary, usually /bin/busybox.
56 Busybox is optimized for size, but enabling the full set of functionality
57 still results in a fairly large executable -- more than 1 megabyte when
58 statically linked. To save space, busybox can be configured with only the
59 set of applets needed for each environment. The minimal configuration, with
60 all applets disabled, produces a 4k executable. (It's useless, but very small.)
62 The manual configurator "make menuconfig" modifies the existing configuration.
63 (For systems without ncurses, try "make config" instead.) The two most
64 interesting starting configurations are "make allnoconfig" (to start with
65 everything disabled and add just what you need), and "make defconfig" (to
66 start with everything enabled and remove what you don't need). If menuconfig
67 is run without an existing configuration, make defconfig will run first to
68 create a known starting point.
70 Other starting configurations (mostly used for testing purposes) include
71 "make allbareconfig" (enables all applets but disables all optional features),
72 "make allyesconfig" (enables absolutely everything including debug features),
73 and "make randconfig" (produce a random configuration). The configs/ directory
74 contains a number of additional configuration files ending in _defconfig which
75 are useful in specific cases. "make help" will list them.
77 Configuring BusyBox produces a file ".config", which can be saved for future
78 use. Run "make oldconfig" to bring a .config file from an older version of
84 Busybox is a single executable that can behave like many different commands,
85 and BusyBox uses the name it was invoked under to determine the desired
86 behavior. (Try "mv busybox ls" and then "./ls -l".)
88 Installing busybox consists of creating symlinks (or hardlinks) to the busybox
89 binary for each applet enabled in busybox, and making sure these symlinks are
90 in the shell's command $PATH. Running "make install" creates these symlinks,
91 or "make install-hardlinks" creates hardlinks instead (useful on systems with
92 a limited number of inodes). This install process uses the file
93 "busybox.links" (created by make), which contains the list of enabled applets
94 and the path at which to install them.
96 Installing links to busybox is not always necessary. The special applet name
97 "busybox" (or with any optional suffix, such as "busybox-static") uses the
98 first argument to determine which applet to behave as, for example
99 "./busybox cat LICENSE". (Running the busybox applet with no arguments gives
100 a list of all enabled applets.) The standalone shell can also call busybox
101 applets without links to busybox under other names in the filesystem. You can
102 also configure a standalone install capability into the busybox base applet,
103 and then install such links at runtime with one of "busybox --install" (for
104 hardlinks) or "busybox --install -s" (for symlinks).
106 If you enabled the busybox shared library feature (libbusybox.so) and want
107 to run tests without installing, set your LD_LIBRARY_PATH accordingly when
108 running the executable:
110 LD_LIBRARY_PATH=`pwd` ./busybox
112 Building out-of-tree:
113 =====================
115 By default, the BusyBox build puts its temporary files in the source tree.
116 Building from a read-only source tree, or building multiple configurations from
117 the same source directory, requires the ability to put the temporary files
120 To build out of tree, cd to an empty directory and configure busybox from there:
122 make KBUILD_SRC=/path/to/source -f /path/to/source/Makefile defconfig
126 Alternately, use the O=$BUILDPATH option (with an absolute path) during the
127 configuration step, as in:
129 make O=/some/empty/directory allyesconfig
130 cd /some/empty/directory
132 make CONFIG_PREFIX=. install
137 Se also the busybox FAQ, under the questions "How can I get started using
138 BusyBox" and "How do I build a BusyBox-based system?" The BusyBox FAQ is
139 available from http://www.busybox.net/FAQ.html