Fubsy is a tool for efficiently building software. In concrete terms, it lets you conditionally (re)build targets from sources based on which sources have changed since the last build. Typically, targets and sources are all files in a directory tree. In theory, they can be any resource on a computer. More abstractly, Fubsy is an engine for conditional execution of actions based on the dependencies between related resources.
EBuild is a software project build, dependency management, and reporting technology. The aim is to be able to tackle any build problem in a structured, declarative, and elegant way. It is written in Java, but can be used to build all manner of projects and is extensible via a plugin interface. It is best compared to something like Maven (and in some respects Ivy). It aims to overcome certain design flaws and the resultant unnecessary complexity. The EBuild build model is general, but plugins need to be written in a JVM compatible language. Existing plugins all deal with the Java ecosystem, so EBuild is most suitable for Java and mixed technology software projects.