diff --git a/min/lib/MrClay/Cli.php b/min/lib/MrClay/Cli.php
new file mode 100644
index 0000000..4c25af7
--- /dev/null
+++ b/min/lib/MrClay/Cli.php
@@ -0,0 +1,321 @@
+<?php 
+
+namespace MrClay;
+
+/**
+ * Front controller for a command line app, handling and validating arguments
+ */
+class Cli {
+    
+    /**
+     * @var array validation errors
+     */
+    public $errors = array();
+    
+    /**
+     * @var array option values available after validation.
+     * 
+     * E.g. array(
+     *      'a' => false              // option was missing
+     *     ,'b' => true               // option was present
+     *     ,'c' => "Hello"            // option had value
+     *     ,'f' => "/home/user/file"  // file path from root
+     *     ,'f.raw' => "~/file"       // file path as given to option
+     * )
+     */
+    public $values = array();
+
+    /**
+     * @var array
+     */
+    public $moreArgs = array();
+
+    /**
+     * @var array
+     */
+    public $debug = array();
+
+    /**
+     * @var array of Cli\Arg
+     */
+    protected $_args = array();
+
+    protected $_stdin = null;
+
+    protected $_stdout = null;
+    
+    /**
+     * @param bool $exitIfNoStdin (default true) Exit() if STDIN is not defined
+     */
+    public function __construct($exitIfNoStdin = true)
+    {
+        if ($exitIfNoStdin && ! defined('STDIN')) {
+            exit('This script is for command-line use only.');
+        }
+    }
+
+    /**
+     * @param Cli\Arg|string $letter
+     * @return Cli\Arg
+     */
+    public function addOptionalArg($letter)
+    {
+        return $this->addArgument($letter, false);
+    }
+
+    /**
+     * @param Cli\Arg|string $letter
+     * @return Cli\Arg
+     */
+    public function addRequiredArg($letter)
+    {
+        return $this->addArgument($letter, true);
+    }
+
+    /**
+     * @param Cli\Arg|string $letter
+     * @param bool $required
+     * @return Cli\Arg
+     */
+    public function addArgument($letter, $required)
+    {
+        if (! $letter instanceof Cli\Arg) {
+            if (is_string($letter)) {
+                $letter = new Cli\Arg($letter, $required);
+            } else {
+                throw new \InvalidArgumentException('Must be letter or MrClay\\Cli\\Arg instance');
+            }
+        }
+        $this->_args[$letter->getLetter()] = $letter;
+        return $letter;
+    }
+    
+    /*
+     * Read and validate options
+     * 
+     * @return bool true if all options are valid
+     */
+    public function validate()
+    {
+        $options = '';
+        $this->errors = array();
+        $this->values = array();
+        $this->_stdin = null;
+        
+        if (isset($GLOBALS['argv'][1]) 
+            && ($GLOBALS['argv'][1] === '-?'
+                || $GLOBALS['argv'][1] === '--help'
+                )) {
+            return false;
+        }
+        
+        $lettersUsed = '';
+        foreach ($this->_args as $arg) {
+            /* @var Cli\Arg $arg  */
+            $letter = $arg->getLetter();
+            $options .= $letter;
+            $lettersUsed .= $letter;
+            
+            if ($arg->mayHaveValue || $arg->mustHaveValue) {
+                $options .= ($arg->mustHaveValue ? ':' : '::');
+            }
+        }
+
+        $this->debug['argv'] = $GLOBALS['argv'];
+        $argvCopy = array_slice($GLOBALS['argv'], 1);
+        $o = getopt($options);
+        $this->debug['getopt_options'] = $options;
+        $this->debug['getopt_return'] = $o;
+
+        foreach ($this->_args as $arg) {
+            /* @var Cli\Arg $arg  */
+            $letter = $arg->getLetter();
+            $this->values[$letter] = false;
+            if (isset($o[$letter])) {
+                if (is_bool($o[$letter])) {
+
+                    // remove from argv copy
+                    $k = array_search("-$letter", $argvCopy);
+                    if ($k !== false) {
+                        array_splice($argvCopy, $k, 1);
+                    }
+
+                    if ($arg->mustHaveValue) {
+                        $this->addError($letter, "Missing value");
+                    } else {
+                        $this->values[$letter] = true;
+                    }
+                } else {
+                    // string
+                    $this->values[$letter] = $o[$letter];
+                    $v =& $this->values[$letter];
+
+                    // remove from argv copy
+                    // first look for -ovalue or -o=value
+                    $pattern = "/^-{$letter}=?" . preg_quote($v, '/') . "$/";
+                    $foundInArgv = false;
+                    foreach ($argvCopy as $k => $argV) {
+                        if (preg_match($pattern, $argV)) {
+                            array_splice($argvCopy, $k, 1);
+                            $foundInArgv = true;
+                            break;
+                        }
+                    }
+                    if (! $foundInArgv) {
+                        // space separated
+                        $k = array_search("-$letter", $argvCopy);
+                        if ($k !== false) {
+                            array_splice($argvCopy, $k, 2);
+                        }
+                    }
+                    
+                    // check that value isn't really another option
+                    if (strlen($lettersUsed) > 1) {
+                        $pattern = "/^-[" . str_replace($letter, '', $lettersUsed) . "]/i";
+                        if (preg_match($pattern, $v)) {
+                            $this->addError($letter, "Value was read as another option: %s", $v);
+                            return false;
+                        }    
+                    }
+                    if ($arg->assertFile || $arg->assertDir) {
+                        if ($v[0] !== '/' && $v[0] !== '~') {
+                            $this->values["$letter.raw"] = $v;
+                            $v = getcwd() . "/$v";
+                        }
+                    }
+                    if ($arg->assertFile) {
+                        if ($arg->useAsInfile) {
+                            $this->_stdin = $v;
+                        } elseif ($arg->useAsOutfile) {
+                            $this->_stdout = $v;
+                        }
+                        if ($arg->assertReadable && ! is_readable($v)) {
+                            $this->addError($letter, "File not readable: %s", $v);
+                            continue;
+                        }
+                        if ($arg->assertWritable) {
+                            if (is_file($v)) {
+                                if (! is_writable($v)) {
+                                    $this->addError($letter, "File not writable: %s", $v);
+                                }
+                            } else {
+                                if (! is_writable(dirname($v))) {
+                                    $this->addError($letter, "Directory not writable: %s", dirname($v));
+                                }
+                            }
+                        }
+                    } elseif ($arg->assertDir && $arg->assertWritable && ! is_writable($v)) {
+                        $this->addError($letter, "Directory not readable: %s", $v);
+                    }
+                }
+            } else {
+                if ($arg->isRequired) {
+                    $this->addError($letter, "Missing");
+                }
+            }
+        }
+        $this->moreArgs = $argvCopy;
+        reset($this->moreArgs);
+        return empty($this->errors);
+    }
+
+    /**
+     * Get the full paths of file(s) passed in as unspecified arguments
+     *
+     * @return array
+     */
+    public function getPathArgs()
+    {
+        $r = $this->moreArgs;
+        foreach ($r as $k => $v) {
+            if ($v[0] !== '/' && $v[0] !== '~') {
+                $v = getcwd() . "/$v";
+                $v = str_replace('/./', '/', $v);
+                do {
+                    $v = preg_replace('@/[^/]+/\\.\\./@', '/', $v, 1, $changed);
+                } while ($changed);
+                $r[$k] = $v;
+            }
+        }
+        return $r;
+    }
+    
+    /**
+     * Get a short list of errors with options
+     * 
+     * @return string
+     */
+    public function getErrorReport()
+    {
+        if (empty($this->errors)) {
+            return '';
+        }
+        $r = "Problems with your options:\n";
+        foreach ($this->errors as $letter => $arr) {
+            $r .= "  $letter : " . implode(', ', $arr) . "\n";
+        }
+        $r .= "\n";
+        return $r;
+    }
+    
+    /**
+     * Get resource of open input stream. May be STDIN or a file pointer
+     * to the file specified by an option with 'STDIN'.
+     *
+     * @return resource
+     */
+    public function openInput()
+    {
+        if (null === $this->_stdin) {
+            return STDIN;
+        } else {
+            $this->_stdin = fopen($this->_stdin, 'rb');
+            return $this->_stdin;
+        }
+    }
+    
+    public function closeInput()
+    {
+        if (null !== $this->_stdin) {
+            fclose($this->_stdin);
+        }
+    }
+    
+    /**
+     * Get resource of open output stream. May be STDOUT or a file pointer
+     * to the file specified by an option with 'STDOUT'. The file will be
+     * truncated to 0 bytes on opening.
+     *
+     * @return resource
+     */
+    public function openOutput()
+    {
+        if (null === $this->_stdout) {
+            return STDOUT;
+        } else {
+            $this->_stdout = fopen($this->_stdout, 'wb');
+            return $this->_stdout;
+        }
+    }
+    
+    public function closeOutput()
+    {
+        if (null !== $this->_stdout) {
+            fclose($this->_stdout);
+        }
+    }
+
+    /**
+     * @param string $letter
+     * @param string $msg
+     * @param string $value
+     */
+    protected function addError($letter, $msg, $value = null)
+    {
+        if ($value !== null) {
+            $value = var_export($value, 1);
+        }
+        $this->errors[$letter][] = sprintf($msg, $value);
+    }
+}
+
diff --git a/min/lib/MrClay/Cli/Arg.php b/min/lib/MrClay/Cli/Arg.php
new file mode 100644
index 0000000..00570b3
--- /dev/null
+++ b/min/lib/MrClay/Cli/Arg.php
@@ -0,0 +1,163 @@
+<?php
+
+namespace MrClay\Cli;
+
+/**
+ * An argument for a CLI app. This specifies the argument, what values it expects and
+ * how it's treated during validation.
+ *
+ * By default, the argument will be assumed to be a letter flag with no value following.
+ *
+ * If the argument may receive a value, call mayHaveValue(). If there's whitespace after the
+ * flag, the value will be returned as true instead of the string.
+ *
+ * If the argument is required, or mustHaveValue() is called, the value will be required and
+ * whitespace is permitted between the flag and its value.
+ *
+ * If the argument AND string BOTH must be present for validation, call assertRequired().
+ *
+ * Use assertFile() or assertDir() to indicate that the argument must return a string value
+ * specifying a file or directory. During validation, the value will be resolved to a
+ * full file/dir path (not necessarily existing!) and the original value will be accessible
+ * via a "*.raw" key. E.g. $cli->values['f.raw']
+ *
+ * Use assertReadable()/assertWritable() to cause the validator to test the file/dir for
+ * read/write permissions respectively.
+ *
+ * @method \MrClay\Cli\Arg mayHaveValue() Assert that the argument, if present, may receive a string value
+ * @method \MrClay\Cli\Arg mustHaveValue() Assert that the argument, if present, must receive a string value
+ * @method \MrClay\Cli\Arg assertFile() Assert that the argument's value must specify a file
+ * @method \MrClay\Cli\Arg assertDir() Assert that the argument's value must specify a directory
+ * @method \MrClay\Cli\Arg assertReadable() Assert that the specified file/dir must be readable
+ * @method \MrClay\Cli\Arg assertWritable() Assert that the specified file/dir must be writable
+ *
+ * @property-read bool isRequired
+ * @property-read bool mayHaveValue
+ * @property-read bool mustHaveValue
+ * @property-read bool assertFile
+ * @property-read bool assertDir
+ * @property-read bool assertReadable
+ * @property-read bool assertWritable
+ * @property-read bool useAsInfile
+ * @property-read bool useAsOutfile
+ */
+class Arg {
+    /**
+     * @return array
+     */
+    public function getDefaultSpec()
+    {
+        return array(
+            'mayHaveValue' => false,
+            'mustHaveValue' => false,
+            'assertFile' => false,
+            'assertDir' => false,
+            'assertReadable' => false,
+            'assertWritable' => false,
+            'useAsInfile' => false,
+            'useAsOutfile' => false,
+        );
+    }
+
+    /**
+     * @var string
+     */
+    protected $letter;
+
+    /**
+     * @var array
+     */
+    protected $spec = array();
+
+    protected $required = false;
+
+    /**
+     * @param string $letter
+     * @param bool $isRequired
+     */
+    public function __construct($letter, $isRequired = false)
+    {
+        if (! preg_match('/^[a-zA-Z]$/', $letter)) {
+            throw new \InvalidArgumentException('$letter must be in [a-zA-z]');
+        }
+        $this->letter = $letter;
+        $this->spec = $this->getDefaultSpec();
+        $this->required = (bool) $isRequired;
+        if ($isRequired) {
+            $this->spec['mustHaveValue'] = true;
+        }
+    }
+
+    /**
+     * Assert that the argument's value points to a writable file. When
+     * CliArgs::openOutput() is called, a write pointer to this file will
+     * be provided.
+     * @return Arg
+     */
+    public function useAsOutfile()
+    {
+        $this->spec['useAsOutfile'] = true;
+        return $this->assertFile()->assertWritable();
+    }
+
+    /**
+     * Assert that the argument's value points to a readable file. When
+     * CliArgs::openInput() is called, a read pointer to this file will
+     * be provided.
+     * @return Arg
+     */
+    public function useAsInfile()
+    {
+        $this->spec['useAsInfile'] = true;
+        return $this->assertFile()->assertReadable();
+    }
+
+    /**
+     * @return mixed
+     */
+    public function getLetter()
+    {
+        return $this->letter;
+    }
+
+    /**
+     * @return array
+     */
+    public function getSpec()
+    {
+        return $this->spec;
+    }
+
+    /**
+     * @param string $name
+     * @param array $args
+     * @return Arg
+     * @throws \BadMethodCallException
+     */
+    public function __call($name, array $args = array())
+    {
+        if (array_key_exists($name, $this->spec)) {
+            $this->spec[$name] = true;
+            if ($name === 'assertFile' || $name === 'assertDir') {
+                $this->spec['mustHaveValue'] = true;
+            }
+        } else {
+            throw new \BadMethodCallException('Method does not exist');
+        }
+        return $this;
+    }
+
+    /**
+     * @param string $name
+     * @return bool|null
+     */
+    public function __get($name)
+    {
+        if (array_key_exists($name, $this->spec)) {
+            return $this->spec[$name];
+        } elseif ($name === 'isRequired') {
+            return $this->required;
+        }
+        return null;
+    }
+}
diff --git a/min_extras/cli/rewrite-uris.php b/min_extras/cli/rewrite-uris.php
new file mode 100755
index 0000000..eb79ca2
--- /dev/null
+++ b/min_extras/cli/rewrite-uris.php
@@ -0,0 +1,56 @@
+#!/usr/bin/php
+<?php
+
+$pathToLib = dirname(dirname(__DIR__)) . '/min/lib';
+
+// needed because of dumb require statements in class files :(
+set_include_path($pathToLib . PATH_SEPARATOR . get_include_path());
+
+// barebones autoloader
+spl_autoload_register(function ($class) use ($pathToLib) {
+    $file = $pathToLib . '/' . str_replace(array('_', '\\'), DIRECTORY_SEPARATOR, $class) . '.php';
+    if (is_file($file)) {
+        require $file;
+        return true;
+    }
+    return false;
+});
+
+$cli = new MrClay\Cli;
+$cli->addRequiredArg('d')->assertDir();
+$cli->addOptionalArg('o')->useAsOutfile();
+$cli->addOptionalArg('v');
+
+if (! $cli->validate()) {
+    echo "USAGE: ./rewrite-uris.php -d DOC_ROOT [-o OUTFILE [-v]] file ...\n";
+    echo "EXAMPLE: ./rewrite-uris.php -v -d../.. ../../min_unit_tests/_test_files/css/paths_rewrite.css ../../min_unit_tests/_test_files/css/comments.css
+    \n";
+    exit(0);
+}
+
+$outfile = $cli->values['o'];
+$verbose = $cli->values['v'];
+$docRoot = $cli->values['d'];
+
+$pathRewriter = function($css, $options) {
+    return Minify_CSS_UriRewriter::rewrite($css, $options['currentDir'], $options['docRoot']);
+};
+
+$fp = $cli->openOutput();
+
+$paths = $cli->getPathArgs();
+$sources = array();
+foreach ($paths as $path) {
+    $sources[] = new Minify_Source(array(
+        'filepath' => $path,
+        'minifier' => $pathRewriter,
+        'minifyOptions' => array('docRoot' => $docRoot),
+    ));
+}
+fwrite($fp, Minify::combine($sources) . "\n");
+
+if ($outfile && $verbose) {
+    echo Minify_CSS_UriRewriter::$debugText . "\n";
+}
+
+$cli->closeOutput();
diff --git a/min_extras/config.php b/min_extras/config.php
index 459fc32..a368703 100644
--- a/min_extras/config.php
+++ b/min_extras/config.php
@@ -11,6 +11,6 @@ $minifyCachePath = isset($min_cachePath)
     : '';
 
 function min_autoload($name) {
-    require str_replace('_', DIRECTORY_SEPARATOR, $name) . '.php';
+    require str_replace(array('_', '\\'), DIRECTORY_SEPARATOR, $name) . '.php';
 }
 spl_autoload_register('min_autoload');