IBM has just published an online article about BusyBox, the single executable file that implements an extensive set of standard Linux commandline utilities in a highly resource-efficient manner. The article explores the purpose of BusyBox, how it works, how to use it, and how to extend it, among other topics.
BusyBox is one of the most widely used open-source applications. It’s used by almost every embedded Linux developer, and can be found on nearly every Linux-based embedded device, not to mention within “normal” Linux servers and desktops (type “busybox –help” on your Linux desktop’s commandline).
Author M. Tim Jones writes, “BusyBox contains simple utilities, such as cat and echo, as well as larger, more complex tools, such as grep, find, mount, and telnet (albeit, with fewer options than the traditional version); some refer to BusyBox as the Swiss Army knife of utilities.”
Jones notes that BusyBox was initially written in 1996 by Bruce Perens, for use on the Debian GNU/Linux setup disk. “The goal was to create a bootable GNU/Linux system on a single floppy disk that could be used as an install and rescue disk,” Jones writes.
The article covers:
- The birth of BusyBox
- How it works
- Configuring and building BusyBox
- Shrinking BusyBox
- Standard commandline options
- Adding new commands
Recently, the BusyBox and uClibc projects joined a conservancy launched by the Software Free Law Center (SFLC) to provide free software projects with “fiscal and administrative services.”
A typical real-time application involves a task performing some operation within a deadline. For example: storing some data, or updating a display. The task often is designed to repeat such activities ad infinitum, beginning each iteration at the occurrence of a hardware interrupt. This interrupt may be caused by a human clicking a button, a temperature reading, data from a visual sensor, or innumerable other possibilities.
