Guard is a command line tool to easily handle events on file system
...Common use cases include: an IDE replacement, web development tools, designing "smart" and "responsive" build systems/workflows, automating various project tasks and installing/monitoring various system services.
RInject is a tool for automated testing of web applications and services. It can be used to test HTTP(S) interfaces for service-level monitoring.
Compared to WebInject, RInject has a more powerful verification- and parsing-engine.