diff --git a/src/Filter/AssetFilter.php b/src/Filter/AssetFilter.php
index 3bea0b77..bc73b689 100644
--- a/src/Filter/AssetFilter.php
+++ b/src/Filter/AssetFilter.php
@@ -82,6 +82,16 @@ public function getDependencies(AssetTarget $file)
         return [];
     }
 
+    /**
+     * Overloaded in filters that can't handle dependencies
+     *
+     * @return boolean True when the filter supports dependencies
+     */
+    public function hasDependencies()
+    {
+        return true;
+    }
+
     /**
      * Run the compressor command and get the output
      *
diff --git a/src/Filter/FilterInterface.php b/src/Filter/FilterInterface.php
index 8c002b77..09922c01 100644
--- a/src/Filter/FilterInterface.php
+++ b/src/Filter/FilterInterface.php
@@ -59,4 +59,11 @@ public function settings(array $settings = null);
      * @return array An array of MiniAsset\File\Local objects.
      */
     public function getDependencies(AssetTarget $target);
+
+    /**
+     * Returns a boolean whether the filter supports dependencies.
+     *
+     * @return boolean True when the filter supports dependencies
+     */
+    public function hasDependencies();
 }
diff --git a/src/Filter/PipeInputFilter.php b/src/Filter/PipeInputFilter.php
new file mode 100644
index 00000000..e33332f2
--- /dev/null
+++ b/src/Filter/PipeInputFilter.php
@@ -0,0 +1,87 @@
+<?php
+/**
+ * MiniAsset
+ * Copyright (c) Mark Story (http://mark-story.com)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) Mark Story (http://mark-story.com)
+ * @since         0.0.1
+ * @license       http://www.opensource.org/licenses/mit-license.php MIT License
+ */
+namespace MiniAsset\Filter;
+
+use MiniAsset\AssetTarget;
+use MiniAsset\Filter\AssetFilter;
+use MiniAsset\Filter\CssDependencyTrait;
+
+/**
+ * Pre-processing filter that adds support for command pipes
+ */
+class PipeInputFilter extends AssetFilter
+{
+    use CssDependencyTrait {
+        getDependencies as getCssDependencies;
+    }
+
+    /**
+     * Settings for PipeInputFilter
+     *
+     * - `ext` File extension used by the filter
+     * - `dependencies` Set to true to calculate SCSS/LESS dependencies
+     * - `optional_dependency_prefix` Filename prefix for dependencies or false
+     * - `command` Command to run the file through
+     * - `path` Sets PATH environment variable
+     */
+    protected $_settings = array(
+        'ext' => '.css',
+        'dependencies' => false,
+        'optional_dependency_prefix' => false,
+        'command' => '/bin/cat',
+        'path' => '/bin',
+    );
+
+    /**
+     * It will use prefixed files if they exist.
+     *
+     * @var string
+     */
+    protected $optionalDependencyPrefix = null;
+
+    public function hasDependencies()
+    {
+        return $this->_settings['dependencies'];
+    }
+
+    public function getDependencies(AssetTarget $file)
+    {
+        if ($this->_settings['dependencies']) {
+            $this->optionalDependencyPrefix = $this->_settings['optional_dependency_prefix'];
+
+            return $this->getCssDependencies($file);
+        }
+
+        return [];
+    }
+
+    /**
+     * Runs command against any files that match the configured extension.
+     *
+     * @param string $filename The name of the input file.
+     * @param string $input The content of the file.
+     * @return string
+     */
+    public function input($filename, $input)
+    {
+        if (substr($filename, strlen($this->_settings['ext']) * -1) !== $this->_settings['ext']) {
+            return $input;
+        }
+        $filename = escapeshellarg($filename);
+        $bin = $this->_settings['command'] . ' ' . $filename;
+        $return = $this->_runCmd($bin, '', array('PATH' => $this->_settings['path']));
+
+        return $return;
+    }
+}
diff --git a/src/Filter/PipeOutputFilter.php b/src/Filter/PipeOutputFilter.php
new file mode 100644
index 00000000..ea3ef34d
--- /dev/null
+++ b/src/Filter/PipeOutputFilter.php
@@ -0,0 +1,47 @@
+<?php
+/**
+ * MiniAsset
+ * Copyright (c) Mark Story (http://mark-story.com)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright     Copyright (c) Mark Story (http://mark-story.com)
+ * @since         0.0.1
+ * @license       http://www.opensource.org/licenses/mit-license.php MIT License
+ */
+namespace MiniAsset\Filter;
+
+use MiniAsset\Filter\AssetFilter;
+
+/**
+ * Output pipe processor
+ */
+class PipeOutputFilter extends AssetFilter
+{
+
+    /**
+     * Settings for PipeOutputFilter
+     *
+     * - `command` Command to execute
+     */
+    protected $_settings = array(
+        'command' => '/bin/cat',
+        'path' => '/bin',
+    );
+
+    /**
+     * Run command against the output and compress it.
+     *
+     * @param string $filename Name of the file being generated.
+     * @param string $input The raw contents for $filename.
+     * @return string Processed contents.
+     */
+    public function output($filename, $input)
+    {
+        $cmd = $this->_settings['command'];
+
+        return $this->_runCmd($cmd, $input, array('PATH' => $this->_settings['path']));
+    }
+}
diff --git a/src/Output/FreshTrait.php b/src/Output/FreshTrait.php
index c78d0a33..b994d6bd 100644
--- a/src/Output/FreshTrait.php
+++ b/src/Output/FreshTrait.php
@@ -90,6 +90,9 @@ public function isFresh(AssetTarget $target)
 
         $filters = $this->filterRegistry->collection($target);
         foreach ($filters->filters() as $filter) {
+            if (!$filter->hasDependencies()) {
+                return false;
+            }
             foreach ($filter->getDependencies($target) as $child) {
                 $time = $child->modifiedTime();
                 if ($time >= $buildTime) {
diff --git a/tests/TestCase/Filter/PipeInputFilterTest.php b/tests/TestCase/Filter/PipeInputFilterTest.php
new file mode 100644
index 00000000..9b85ee3c
--- /dev/null
+++ b/tests/TestCase/Filter/PipeInputFilterTest.php
@@ -0,0 +1,96 @@
+<?php
+/**
+ * MiniAsset
+ * Copyright (c) Mark Story (http://mark-story.com)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright Copyright (c) Mark Story (http://mark-story.com)
+ * @since     0.0.1
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT License
+ */
+namespace MiniAsset\Test\TestCase\Filter;
+
+use MiniAsset\AssetTarget;
+use MiniAsset\File\Local;
+use MiniAsset\Filter\PipeInputFilter;
+use PHPUnit\Framework\TestCase;
+
+class PipeInputFilterTest extends TestCase
+{
+
+    public function setUp(): void
+    {
+        parent::setUp();
+        $this->_cssDir = APP . 'css' . DS;
+        $this->filter = new PipeInputFilter();
+        $this->filter->settings([
+            'paths' => [$this->_cssDir],
+            'ext' => '.scss',
+        ]);
+    }
+
+    public function testParsing()
+    {
+        $this->filter->settings(array('command' => '/bin/cat'));
+
+        $content = file_get_contents($this->_cssDir . 'test.scss');
+        $result = $this->filter->input($this->_cssDir . 'test.scss', $content);
+        $expected = file_get_contents($this->_cssDir . 'test.scss');
+        $this->assertEquals($expected, $result);
+    }
+
+    public function testGetDependenciesFalse()
+    {
+        $this->filter->settings(array(
+            'dependencies' => false,
+            'optional_dependency_prefix' => false,
+        ));
+
+        $files = [
+            new Local($this->_cssDir . 'test.scss')
+        ];
+        $target = new AssetTarget('test.css', $files);
+        $result = $this->filter->getDependencies($target);
+
+        $this->assertEmpty($result);
+    }
+
+    public function testGetDependenciesTrue()
+    {
+        $this->filter->settings(array(
+            'dependencies' => true,
+            'optional_dependency_prefix' => '_',
+        ));
+
+        $files = [
+            new Local($this->_cssDir . 'test.scss')
+        ];
+        $target = new AssetTarget('test.css', $files);
+        $result = $this->filter->getDependencies($target);
+
+        $this->assertCount(3, $result);
+        $this->assertEquals('colors.scss', $result[0]->name());
+        $this->assertEquals('_utilities.scss', $result[1]->name());
+        $this->assertEquals('_reset.scss', $result[2]->name());
+    }
+
+    public function testGetDependenciesMissingDependency()
+    {
+        $this->filter->settings(array(
+            'dependencies' => true,
+            'optional_dependency_prefix' => '_',
+        ));
+
+        $files = [
+            new Local($this->_cssDir . 'broken.scss')
+        ];
+        $target = new AssetTarget('test.css', $files);
+        $result = $this->filter->getDependencies($target);
+
+        $this->assertCount(1, $result);
+        $this->assertEquals('colors.scss', $result[0]->name());
+    }
+}
diff --git a/tests/TestCase/Filter/PipeOutputFilterTest.php b/tests/TestCase/Filter/PipeOutputFilterTest.php
new file mode 100644
index 00000000..216187c8
--- /dev/null
+++ b/tests/TestCase/Filter/PipeOutputFilterTest.php
@@ -0,0 +1,36 @@
+<?php
+/**
+ * MiniAsset
+ * Copyright (c) Mark Story (http://mark-story.com)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright Copyright (c) Mark Story (http://mark-story.com)
+ * @since     0.0.1
+ * @license   http://www.opensource.org/licenses/mit-license.php MIT License
+ */
+namespace MiniAsset\Test\TestCase\Filter;
+
+use MiniAsset\Filter\PipeOutputFilter;
+use PHPUnit\Framework\TestCase;
+
+class PipeOutputFilterTest extends TestCase
+{
+
+    public function setUp(): void
+    {
+        parent::setUp();
+        $this->_cssDir = APP . 'css' . DS;
+        $this->filter = new PipeOutputFilter();
+    }
+
+    public function testOutput()
+    {
+        $content = file_get_contents($this->_cssDir . 'unminified.css');
+        $result = $this->filter->output($this->_cssDir . 'unminified.css', $content);
+        $expected = file_get_contents($this->_cssDir . 'unminified.css');
+        $this->assertEquals($expected, $result);
+    }
+}