Another abstract syntax tree–based code search tool that received our attention is Sourcegraph. In contrast to Comby, which is open source, Sourcegraph is a commercial tool (with a 10-user free tier). Sourcegraph is particularly suited for searching, navigating or cross-referencing in large codebases. The cloud-hosted version can be accessed through Sourcegraph's website and is designed to search publicly available open-source repositories. Whereas Comby is a lightweight command-line tool for automating repetitive tasks, Sourcegraph's emphasis is on interactive developer tools for understanding and navigating large code bases. Unlike Comby's
sed-like interface, Sourcegraph's automated code rewriting capability is driven from a UI, allowing users to review changes before they're made. Because Sourcegraph is a hosted service, it also has the ability to continuously monitor code bases and send alerts when a match occurs.