Debugging
Finding + fixing defects in code. Term from Grace Hopper 1947 (literal insect in the Harvard Mark II relay). Tools: breakpoints, log statements, stack traces, profiler, memory analyzer.
Classic debuggers: gdb (C/C++), lldb (LLVM), pdb (Python), DevTools (browsers), VS Code debugger (LSP-based). Print debugging is still most common in practice despite classical arguments against. Rubber-duck debugging: explain the problem to a rubber duck → often solves itself. Reverse debugging (rr on Linux) allows step-backwards. Postmortem debugging: analyze core dump afterwards. "Always be debugging" — when you read new code, read it as if hunting bugs.