ast-grep | structural search/rewrite tool for many languages

# AST-GREP > Find Code by Syntax ast-grep(sg) is a fast and polyglot tool for code structural search, lint, rewriting at large scale. ## Table of Contents ### Guide - [Quick Start](/guide/quick-start.md): Learn how to install ast-grep and use it to quickly find and refactor code in your codebase. This powerful tool can help you save time and improve the quality of your code. - [Pattern Syntax](/guide/pattern-syntax.md) - [Rule Essentials](/guide/rule-config.md) - [Scan Your Project!](/guide/scan-project.md) - [Rewrite Code](/guide/rewrite-code.md) - [Command Line Tooling Overview](/guide/tooling-overview.md) - [API Usage](/guide/api-usage.md) #### Rule Essentials - [Atomic Rule](/guide/rule-config/atomic-rule.md) - [Relational Rules](/guide/rule-config/relational-rule.md) - [Composite Rule](/guide/rule-config/composite-rule.md) - [Reusing Rule as Utility](/guide/rule-config/utility-rule.md) #### Project Setup - [Project Configuration](/guide/project/project-config.md) - [Lint Rule](/guide/project/lint-rule.md) - [Test Your Rule](/guide/test-rule.md) - [Handle Error Reports](/guide/project/severity.md) #### Rewrite Code - [`transform` Code in Rewrite](/guide/rewrite/transform.md) - [Rewriter in Fix](/guide/rewrite/rewriter.md) #### Tooling Overview - [Editor Integration](/guide/tools/editors.md) - [JSON Mode](/guide/tools/json.md) #### API Usage - [JavaScript API](/guide/api-usage/js-api.md) - [Python API](/guide/api-usage/py-api.md) - [Performance Tip for napi usage](/guide/api-usage/performance-tip.md) ### Examples - [C](/catalog/c.md) - [Cpp](/catalog/cpp.md) - [Go](/catalog/go.md) - [HTML](/catalog/html.md) - [Java](/catalog/java.md) - [Kotlin](/catalog/kotlin.md) - [Python](/catalog/python.md) - [Ruby](/catalog/ruby.md) - [Rust](/catalog/rust.md) - [TypeScript](/catalog/typescript.md) - [TSX](/catalog/tsx.md) - [YAML](/catalog/yaml.md) ### Cheat Sheet - [Rule Cheat Sheet](/cheatsheet/rule.md) - [Config Cheat Sheet](/cheatsheet/yaml.md) ### Re