BeeDiff / Beesoft Differ:
一个基于Qt4,C/C++开发的GUI Diff工具,苗条得很,源码包 beediff_1.5_src.tar.gz 只有68KB, 除了作为Diff工具,还可以方便学习Qt, C++.

软件主页:
http://www.beesoft.org
作者 Piotr Pszczolkowski:
学校里的时候他是个物理学生,现在做“实时系统”软件开发,他的站点还同时发布另三个软件:

Cobras:
Cobras IDE is an Open Source development environment dedicated for work with Qt.
As external tools Cobras requires only gcc and gdb.
There are tools, that normaly are installed on every Linux instalation (I'm thinking so).
Program is easy, very functional and helpfull. Is stable and very fast.

Tracer:
Beesoft Tracer is a suite of tools for a remote real time debugging of running program.
All elements are wrote in pure C++ with using STL library.
The communication between elements is via sockets: so called unix domain socket and TCP/IP.

BSCommander:
没有介绍,看截图,貌似为针对实时系统的一个远程控制软件.

四个工具都以 GNU GPL 发布, Piotr 是个好人