Annotation of /trunk/mkinitrd-magellan/busybox/INSTALL

Building:
=========

The BusyBox build process is similar to the Linux kernel build:

  make menuconfig     # This creates a file called ".config"
  make                # This creates the "busybox" executable
  make install        # or make PREFIX=/path/from/root install

The full list of configuration and install options is available by typing:

  make help

Quick Start:
============

The easy way to try out BusyBox for the first time, without having to install
it, is to enable all features and then use "standalone shell" mode with a
blank command $PATH.

To enable all features, use "make defconfig", which produces the largest
general-purpose configuration.  (It's allyesconfig minus debugging options,
optional packaging choices, and a few special-purpose features requiring
extra configuration to use.)

  make defconfig
  make
  PATH= ./busybox ash

Standalone shell mode causes busybox's built-in command shell to run
any built-in busybox applets directly, without looking for external
programs by that name.  Supplying an empty command path (as above) means
the only commands busybox can find are the built-in ones.

Note that the standalone shell requires CONFIG_BUSYBOX_EXEC_PATH
to be set appropriately, depending on whether or not /proc/self/exe is
available or not. If you do not have /proc, then point that config option
to the location of your busybox binary, usually /bin/busybox.

Configuring Busybox:
====================

Busybox is optimized for size, but enabling the full set of functionality
still results in a fairly large executable -- more than 1 megabyte when
statically linked.  To save space, busybox can be configured with only the
set of applets needed for each environment.  The minimal configuration, with
all applets disabled, produces a 4k executable.  (It's useless, but very small.)

The manual configurator "make menuconfig" modifies the existing configuration.
(For systems without ncurses, try "make config" instead.) The two most
interesting starting configurations are "make allnoconfig" (to start with
everything disabled and add just what you need), and "make defconfig" (to
start with everything enabled and remove what you don't need).  If menuconfig
is run without an existing configuration, make defconfig will run first to
create a known starting point.

Other starting configurations (mostly used for testing purposes) include
"make allbareconfig" (enables all applets but disables all optional features),
"make allyesconfig" (enables absolutely everything including debug features),
and "make randconfig" (produce a random configuration).

Configuring BusyBox produces a file ".config", which can be saved for future
use.  Run "make oldconfig" to bring a .config file from an older version of
busybox up to date.

Installing Busybox:
===================

Busybox is a single executable that can behave like many different commands,
and BusyBox uses the name it was invoked under to determine the desired
behavior.  (Try "mv busybox ls" and then "./ls -l".)

Installing busybox consists of creating symlinks (or hardlinks) to the busybox
binary for each applet enabled in busybox, and making sure these symlinks are
in the shell's command $PATH.  Running "make install" creates these symlinks,
or "make install-hardlinks" creates hardlinks instead (useful on systems with
a limited number of inodes).  This install process uses the file
"busybox.links" (created by make), which contains the list of enabled applets
and the path at which to install them.

Installing links to busybox is not always necessary.  The special applet name
"busybox" (or with any optional suffix, such as "busybox-static") uses the
first argument to determine which applet to behave as, for example
"./busybox cat LICENSE".  (Running the busybox applet with no arguments gives
a list of all enabled applets.) The standalone shell can also call busybox
applets without links to busybox under other names in the filesystem.  You can
also configure a standaone install capability into the busybox base applet,
and then install such links at runtime with one of "busybox --install" (for
hardlinks) or "busybox --install -s" (for symlinks).

If you enabled the busybox shared library feature (libbusybox.so) and want
to run tests without installing, set your LD_LIBRARY_PATH accordingly when
running the executable:

  LD_LIBRARY_PATH=`pwd` ./busybox

Building out-of-tree:
=====================

By default, the BusyBox build puts its temporary files in the source tree.
Building from a read-only source tree, or building multiple configurations from
the same source directory, requires the ability to put the temporary files
somewhere else.

To build out of tree, cd to an empty directory and configure busybox from there:

  make -f /path/to/source/Makefile defconfig
  make
  make install

Alternately, use the O=$BUILDPATH option (with an absolute path) during the
configuration step, as in:

  make O=/some/empty/directory allyesconfig
  cd /some/empty/directory
  make
  make PREFIX=. install

More Information:
=================

Se also the busybox FAQ, under the questions "How can I get started using
BusyBox" and "How do I build a BusyBox-based system?"  The BusyBox FAQ is
available from http://www.busybox.net/FAQ.html or as the file
docs/busybox.net/FAQ.html in this tarball.
1	niro	532	Building:
2			=========
3
4			The BusyBox build process is similar to the Linux kernel build:
5
6			make menuconfig # This creates a file called ".config"
7			make # This creates the "busybox" executable
8			make install # or make PREFIX=/path/from/root install
9
10			The full list of configuration and install options is available by typing:
11
12			make help
13
14			Quick Start:
15			============
16
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
19			blank command $PATH.
20
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.)
25
26			make defconfig
27			make
28			PATH= ./busybox ash
29
30			Standalone shell mode causes busybox's built-in command shell to run
31			any built-in busybox applets directly, without looking for external
32			programs by that name. Supplying an empty command path (as above) means
33			the only commands busybox can find are the built-in ones.
34
35			Note that the standalone shell requires CONFIG_BUSYBOX_EXEC_PATH
36			to be set appropriately, depending on whether or not /proc/self/exe is
37			available or not. If you do not have /proc, then point that config option
38			to the location of your busybox binary, usually /bin/busybox.
39
40			Configuring Busybox:
41			====================
42
43			Busybox is optimized for size, but enabling the full set of functionality
44			still results in a fairly large executable -- more than 1 megabyte when
45			statically linked. To save space, busybox can be configured with only the
46			set of applets needed for each environment. The minimal configuration, with
47			all applets disabled, produces a 4k executable. (It's useless, but very small.)
48
49			The manual configurator "make menuconfig" modifies the existing configuration.
50			(For systems without ncurses, try "make config" instead.) The two most
51			interesting starting configurations are "make allnoconfig" (to start with
52			everything disabled and add just what you need), and "make defconfig" (to
53			start with everything enabled and remove what you don't need). If menuconfig
54			is run without an existing configuration, make defconfig will run first to
55			create a known starting point.
56
57			Other starting configurations (mostly used for testing purposes) include
58			"make allbareconfig" (enables all applets but disables all optional features),
59			"make allyesconfig" (enables absolutely everything including debug features),
60			and "make randconfig" (produce a random configuration).
61
62			Configuring BusyBox produces a file ".config", which can be saved for future
63			use. Run "make oldconfig" to bring a .config file from an older version of
64			busybox up to date.
65
66			Installing Busybox:
67			===================
68
69			Busybox is a single executable that can behave like many different commands,
70			and BusyBox uses the name it was invoked under to determine the desired
71			behavior. (Try "mv busybox ls" and then "./ls -l".)
72
73			Installing busybox consists of creating symlinks (or hardlinks) to the busybox
74			binary for each applet enabled in busybox, and making sure these symlinks are
75			in the shell's command $PATH. Running "make install" creates these symlinks,
76			or "make install-hardlinks" creates hardlinks instead (useful on systems with
77			a limited number of inodes). This install process uses the file
78			"busybox.links" (created by make), which contains the list of enabled applets
79			and the path at which to install them.
80
81			Installing links to busybox is not always necessary. The special applet name
82			"busybox" (or with any optional suffix, such as "busybox-static") uses the
83			first argument to determine which applet to behave as, for example
84			"./busybox cat LICENSE". (Running the busybox applet with no arguments gives
85			a list of all enabled applets.) The standalone shell can also call busybox
86			applets without links to busybox under other names in the filesystem. You can
87			also configure a standaone install capability into the busybox base applet,
88			and then install such links at runtime with one of "busybox --install" (for
89			hardlinks) or "busybox --install -s" (for symlinks).
90
91			If you enabled the busybox shared library feature (libbusybox.so) and want
92			to run tests without installing, set your LD_LIBRARY_PATH accordingly when
93			running the executable:
94
95			LD_LIBRARY_PATH=`pwd` ./busybox
96
97			Building out-of-tree:
98			=====================
99
100			By default, the BusyBox build puts its temporary files in the source tree.
101			Building from a read-only source tree, or building multiple configurations from
102			the same source directory, requires the ability to put the temporary files
103			somewhere else.
104
105			To build out of tree, cd to an empty directory and configure busybox from there:
106
107			make -f /path/to/source/Makefile defconfig
108			make
109			make install
110
111			Alternately, use the O=$BUILDPATH option (with an absolute path) during the
112			configuration step, as in:
113
114			make O=/some/empty/directory allyesconfig
115			cd /some/empty/directory
116			make
117			make PREFIX=. install
118
119			More Information:
120			=================
121
122			Se also the busybox FAQ, under the questions "How can I get started using
123			BusyBox" and "How do I build a BusyBox-based system?" The BusyBox FAQ is
124			available from http://www.busybox.net/FAQ.html or as the file
125			docs/busybox.net/FAQ.html in this tarball.