Embedded Linux Primer: A Practical Real-World Approach

11.1. Introduction to BusyBox

BusyBox has gained tremendous popularity in the embedded Linux community. It is remarkably easy to configure, compile, and use, and it has the potential to significantly reduce the overall system resources required to support a wide collection of common Linux utilities. BusyBox provides compact replacements for many traditional full-blown utilities found on most desktop and embedded Linux distributions. Examples include the file utilities such as ls, cat, cp, dir, head, and tail; general utilities such as dmesg, kill, halt, fdisk, mount, umount; and many more. BusyBox also provides support for more complex operations, such as ifconfig, netstat, route, and other network utilities.

BusyBox is modular and highly configurable, and can be tailored to suit your particular requirements. The package includes a configuration utility similar to that used to configure the Linux kernel and will, therefore, seem quite familiar.

The commands in BusyBox are generally simpler implementations than their full-blown counterparts. In some cases, only a subset of the usual command line options is supported. In practice, however, you will find that the BusyBox subset of command functionality is more than sufficient for most general embedded requirements.

11.1.1. BusyBox is Easy

If you are able to configure and build the Linux kernel, you will find BusyBox very straightforward to configure, build, and install. The steps are similar:

1. Execute a configuration utility and enable your choice of features

2. Run make dep to build a dependency tree

3. Run make to build the package

4. Install the binary and a series of symbolic links^[1] on your target system

   ^[1] We cover the details of symbolic links shortly.

You can build and install BusyBox on your development workstation or your target embedded system. BusyBox works equally well in both environments. However, you must take care when installing on your development workstation that you keep it isolated in a working directory, to avoid overwriting your system's startup files or primary utilities.