Beaver is an Early AdVanced EditoR, for Linux and other Unices (and even Windows); in other words, it's a text editor that is intended to be light-weight, but full of useful features for programming, from editing of web sites to C coding. It is based upon the GTK+ toolkit, supports many languages, and offers functions such as automatic indentation and syntax highlighting.
BlueJ is an interactive Java development environment. It provides a unique user interface that presents a graphical display of the application classes and their relationships, and it lets users interactively create objects of any class. Once objects have been created, users can interact with them directly. This interaction mechanism allows for much greater testing and experimentation than in conventional environments. BlueJ is suited for teaching and learning OO and Java.
Boxes is a text filter that can draw any kind of box around its input text. Box design choices range from simple boxes to complex ASCII art. A box can also be removed and repaired, even if it has been badly damaged by editing of the text inside. Since the generated boxes may be open on any side, the program can also be used to create regional comments in any programming language. New box designs of all sorts can easily be added and shared by appending to a free format configuration file. In addition to being a command line tool, Boxes integrates well with any text editor that supports filters.
Racket (formerly PLT Scheme) is a programming language suitable for implementation tasks ranging from scripting to application development, including GUIs, Web services, etc. It includes the DrRacket programming environment, a virtual machine with a just-in-time compiler, tools for creating stand-alone executables, the Racket Web server, extensive libraries, documentation for both beginners and experts, and more. It supports the creation of new programming languages through a rich, expressive syntax system. Example languages include Typed Racket, ACL2, FrTime, and Lazy Racket.
e3 is a full-screen, user-friendly text editor with an interface similar to that of either WordStar, Emacs, Pico, Nedit, or vi. It's heavily optimized for size and independent of libc or any other libraries, making it useful for mini-Linux distributions and rescue disks. The assembler version supports Linux, FreeBSD, OpenBSD, NetBSD, Win9x, QNX, Atheos, BeOS, ELKS, and DOS. There is also a separately distributed version written in C which supports some other Unix versions and CygWin. It is also possible to use regular expressions by using child processes like sed. e3 has a built in arithmetic calculator.