Comby vs Understand

Comby is a free, open-source tool for searching and changing code structure with lightweight templates. It recognizes basic syntax in code, strings, and comments across many languages, with parsers listed for C/C++, C#, Go, Java, JavaScript, Python, Rust, Swift, and TypeScript, plus a generic matcher for other formats. The project targets large refactors and one-off changes, and an interactive review mode lets users inspect proposed edits. Comby can run from its command line, Python bindings, or HTTP requests sent to a server on your machine. Installation instructions cover macOS with Homebrew, Ubuntu, Windows through Ubuntu on WSL, and Docker; building from source is also described. Linked projects include an Emacs package and a prototype VS Code extension. Other uses include structural code search, compiler fuzzing, test-case reduction, editor find and replace, and academic research. Comby matches balanced delimiters while accounting for comments and string literals, and supports regex search. It is self-hosted and available for API, Linux, macOS, and Windows use. The Apache-2.0 license is identified in the public repository.

Understand is a static analysis and code-comprehension tool from SciTools. It builds a cross-referenced model of source code without executing it, then helps users explore relationships through its Information Browser, call trees, dependency analysis, and visual graphs, including butterfly and control-flow views. It also provides metrics, CodeCheck, version comparison, APIs, a command-line interface, and AI chat. Supported languages include C/C++, C#, Fortran, Java, Python, Rust, VHDL, Visual Basic, and web languages such as HTML, CSS, JavaScript, TypeScript, PHP, and XML. It runs on Windows 11, specified Linux distributions, and macOS Monterey or later; command-line automation, CI, and an official Docker image are also available. The VS Code extension is separately licensed. Local AI keeps code and prompts on the user's hardware, while cloud AI sends requests with code context to the selected provider. Offline use is supported with offline licensing. Pricing includes a free plan and paid subscriptions from $100/user/mo (annual).