<li class="feature">

<h2>Search and Rewrite</h2>

ast-grep is a code tool for <a href="/guide/quick-start.html">structural search and replace</a>.

It is like syntax-aware grep/sed!

You can write code <a href="/guide/pattern-syntax.html">patterns</a> to locate and modify code,

based on AST, in thousands of files, <a href="/guide/tooling-overview.html#interactive-mode">interactively</a>.

<code class="vp-code">

<span>ast-grep</span> -p '$A && $A()' -r '$A?.()'

<img src='/image/search-replace.png' width="2004" height="1462"/>

</li>

<li class="feature">

<hr/>

<div class="description">

<h2>Scan as Linter</h2>

<p>

ast-grep is a versatile and flexible tool for <a href="/guide/scan-project.html">linting</a> code with AST patterns.

You can easily add new customized rules with <a href="/guide/rule-config.html">intuitive syntax</a> and enjoy pretty error reporting out of box.

</p>

<code class="vp-code">

<span>ast-grep</span> scan

</code>

</div>

<img src='/image/yaml-scan.png' width="2004" height="1462"/>

</li>

<li class="feature">

<hr/>

<div class="description">

<h2>Programmatic Usage</h2>

<p>

ast-grep also provides <a href="/guide/api-usage/js-api.html">node-js binding</a> to access syntax trees programmatically.

You can use jQuery like <a href="/reference/api.html#napi">utility methods</a> to traverse syntax tree nodes.

Node API also has opt-in <a href="/blog/typed-napi.html">type safety</a>.

</p>

<code class="vp-code">

npm install <span>@ast-grep/napi</span>

</code>

</div>

<img src='/image/sg-napi.png' width="2004" height="1462"/>