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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 GNU coreutils, util-linux, etc. 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 /dev, /etc, and a Linux kernel.
BusyBox provides a fairly complete POSIX environment for any small or embedded
BusyBox is extremely configurable. This allows you to include only the
components you need, thereby reducing binary size. Run 'make config' or 'make
menuconfig' to select the functionality that you wish to enable. Then run
'make' to compile BusyBox using your configuration.
After the compile has finished, you should use 'make install' to install
BusyBox. This will install the 'bin/busybox' binary, in the target directory
specified by CONFIG_PREFIX. CONFIG_PREFIX can be set when configuring BusyBox,
or you can specify an alternative location at install time (i.e., with a
command line like 'make CONFIG_PREFIX=/tmp/foo install'). If you enabled
any applet installation scheme (either as symlinks or hardlinks), these will
also be installed in the location pointed to by CONFIG_PREFIX.
BusyBox is a multi-call binary. A multi-call binary is an executable program
that performs the same job as more than one utility program. That means there
is just a single BusyBox binary, but that single binary acts like a large
number of utilities. This allows BusyBox to be smaller since all the built-in
utility programs (we call them applets) can share code for many common operations.
You can also invoke BusyBox by issuing a command as an argument on the
command line. For example, entering
will also cause BusyBox to behave as 'ls'.
Of course, adding '/bin/busybox' into every command would be painful. So most
people will invoke BusyBox using links to the BusyBox binary.
For example, entering
ln -s /bin/busybox ls
will cause BusyBox to behave as 'ls' (if the 'ls' command has been compiled
into BusyBox). Generally speaking, you should never need to make all these
links yourself, as the BusyBox build system will do this for you when you run
the 'make install' command.
If you invoke BusyBox with no arguments, it will provide you with a list of the
applets that have been compiled into your BusyBox binary.
=head1 COMMON OPTIONS
Most BusyBox commands support the B<--help> argument to provide a terse runtime
description of their behavior. If the CONFIG_FEATURE_VERBOSE_USAGE option has
been enabled, more detailed usage information will also be available.
Currently defined functions include: