@stdlib/regexp/extname-posix/README.md

Regular expressions.

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# reExtnamePosix

> [Regular expression][regexp] to capture a [POSIX][posix] filename extension.

<section class="usage">

## Usage

```javascript
var reExtnamePosix = require( '@stdlib/regexp/extname-posix' );
```

#### reExtnamePosix()

Returns a [regular expression][regexp] to capture a [POSIX][posix] filename extension.

```javascript
var RE_EXTNAME_POSIX = reExtnamePosix();
var ext = RE_EXTNAME_POSIX.exec( 'index.js' )[ 1 ];
// returns '.js'
```

#### reExtnamePosix.REGEXP

[Regular expression][regexp] to capture a [POSIX][posix] filename extension.

```javascript
var ext = reExtnamePosix.REGEXP.exec( 'index.js' )[ 1 ];
// returns '.js'
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   When executed against dotfile filenames (e.g., `.gitignore`), the [regular expression][regexp] does **not** capture the basename as a filename extension.

    ```javascript
    var ext = reExtnamePosix.REGEXP.exec( '.bash_profile' )[ 1 ];
    // returns ''

    ext = reExtnamePosix.REGEXP.exec( '.travis.yml' )[ 1 ];
    // returns '.yml'
    ```

</section>

<!-- /.notes -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var reExtnamePosix = require( '@stdlib/regexp/extname-posix' );

var RE_EXTNAME_POSIX = reExtnamePosix();
var ext;

ext = RE_EXTNAME_POSIX.exec( 'index.js' )[ 1 ];
// returns '.js'

ext = RE_EXTNAME_POSIX.exec( '/foo/bar/home.html' )[ 1 ];
// returns '.html'

ext = RE_EXTNAME_POSIX.exec( 'foo/file.pdf' )[ 1 ];
// returns '.pdf'

ext = RE_EXTNAME_POSIX.exec( 'beep.' )[ 1 ];
// returns '.'

ext = RE_EXTNAME_POSIX.exec( '' )[ 1 ];
// returns ''

ext = RE_EXTNAME_POSIX.exec( '/foo/bar/file' )[ 1 ];
// returns ''

ext = RE_EXTNAME_POSIX.exec( '/foo/bar/.gitignore' )[ 1 ];
// returns ''
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/regexp/extname`][@stdlib/regexp/extname]</span><span class="delimiter">: </span><span class="description">return a regular expression to capture a filename extension.</span>
-   <span class="package-name">[`@stdlib/regexp/extname-windows`][@stdlib/regexp/extname-windows]</span><span class="delimiter">: </span><span class="description">return a regular expression to capture a Windows filename extension.</span>
-   <span class="package-name">[`@stdlib/utils/extname`][@stdlib/utils/extname]</span><span class="delimiter">: </span><span class="description">return a filename extension.</span>

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="links">

[regexp]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions

[posix]: https://en.wikipedia.org/wiki/POSIX

<!-- <related-links> -->

[@stdlib/regexp/extname]: https://github.com/stdlib-js/regexp/tree/main/extname

[@stdlib/regexp/extname-windows]: https://github.com/stdlib-js/regexp/tree/main/extname-windows

[@stdlib/utils/extname]: https://www.npmjs.com/package/@stdlib/utils-extname

<!-- </related-links> -->

</section>

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