A pre-commit hook to make PHP code PSR-2 compliant, check for syntax error

php-cs-fixer-pre-commit.php

#!/usr/bin/php
<?php
/**
 * .git/hooks/pre-commit
 * 
 * This pre-commit hooks will check for PHP error (lint), and make sure the code
 * is PSR compliant.
 * 
 * Dependecy: PHP-CS-Fixer (https://github.com/fabpot/PHP-CS-Fixer)
 * 
 * @author  Mardix  http://github.com/mardix 
 * @since   Sept 4 2012
 * 
 */

/**
 * collect all files which have been added, copied or
 * modified and store them in an array called output
 */
exec('git diff --cached --name-status --diff-filter=ACM', $output);

foreach ($output as $file) {
    
    $fileName = trim(substr($file, 1) );

    /**
     * Only PHP file
     */
    if (pathinfo($fileName,PATHINFO_EXTENSION) == "php") {

        /**
         * Check for error
         */
        $lint_output = array();
        exec("php -l " . escapeshellarg($fileName), $lint_output, $return);

        if ($return == 0) {
 
        /**
         * PHP-CS-Fixer && add it back
         */
          exec("php-cs-fixer fix {$fileName} --level=all; git add {$fileName}");

        } else {
            
           echo implode("\n", $lint_output), "\n"; 
           
           exit(1);
           
        }

    }

}

exit(0);