Sysdig is a mature, open-source system monitoring and troubleshooting CLI tool that instruments the Linux kernel to capture system calls and other OS events. It provides a rich curses-based interactive UI (csysdig) and an extensible Lua chisel framework for real-time analysis of CPU, I/O, network, security, and container metrics. The codebase is predominantly C++ with a Lua scripting layer, and includes a comprehensive plugin system for alternative event sources (e.g., gVisor, custom plugins). It also ships a large set of kernel driver build configurations (driverkit) for supporting many Linux distributions and kernel versions. The architecture is a classic CLI application with a modular design: libsinsp for event introspection, chisels for analysis, and a curses UI for visualization. The project is actively maintained by the Sysdig team and the Falco community, with regular commits and CI pipelines.