diff --git a/src/Symfony/Component/Console/Application.php b/src/Symfony/Component/Console/Application.php
index badcce6473..0d66598204 100644
--- a/src/Symfony/Component/Console/Application.php
+++ b/src/Symfony/Component/Console/Application.php
@@ -1161,7 +1161,7 @@ class Application
             $lines[] = str_pad($line, $width);
             $line = $char;
         }
-        if (strlen($line)) {
+        if ('' !== $line) {
             $lines[] = count($lines) ? str_pad($line, $width) : $line;
         }
 
diff --git a/src/Symfony/Component/Console/Formatter/OutputFormatter.php b/src/Symfony/Component/Console/Formatter/OutputFormatter.php
index a053ac6ba0..331b204fec 100644
--- a/src/Symfony/Component/Console/Formatter/OutputFormatter.php
+++ b/src/Symfony/Component/Console/Formatter/OutputFormatter.php
@@ -33,7 +33,7 @@ class OutputFormatter implements OutputFormatterInterface
      */
     public static function escape($text)
     {
-        return preg_replace('/([^\\\\]?)</is', '$1\\<', $text);
+        return preg_replace('/([^\\\\]?)</', '$1\\<', $text);
     }
 
     /**
@@ -146,7 +146,7 @@ class OutputFormatter implements OutputFormatterInterface
         $offset = 0;
         $output = '';
         $tagRegex = '[a-z][a-z0-9_=;-]*';
-        preg_match_all("#<(($tagRegex) | /($tagRegex)?)>#isx", $message, $matches, PREG_OFFSET_CAPTURE);
+        preg_match_all("#<(($tagRegex) | /($tagRegex)?)>#ix", $message, $matches, PREG_OFFSET_CAPTURE);
         foreach ($matches[0] as $i => $match) {
             $pos = $match[1];
             $text = $match[0];
diff --git a/src/Symfony/Component/Console/Shell.php b/src/Symfony/Component/Console/Shell.php
index b3cbf16fa8..d0bcb7ee8a 100644
--- a/src/Symfony/Component/Console/Shell.php
+++ b/src/Symfony/Component/Console/Shell.php
@@ -207,7 +207,7 @@ EOF;
         } else {
             $this->output->write($this->getPrompt());
             $line = fgets(STDIN, 1024);
-            $line = (!$line && strlen($line) == 0) ? false : rtrim($line);
+            $line = (false === $line || '' === $line) ? false : rtrim($line);
         }
 
         return $line;
diff --git a/src/Symfony/Component/DependencyInjection/Dumper/GraphvizDumper.php b/src/Symfony/Component/DependencyInjection/Dumper/GraphvizDumper.php
index fdd71b36ee..ed4f0b1fb3 100644
--- a/src/Symfony/Component/DependencyInjection/Dumper/GraphvizDumper.php
+++ b/src/Symfony/Component/DependencyInjection/Dumper/GraphvizDumper.php
@@ -271,7 +271,7 @@ class GraphvizDumper extends Dumper
      */
     private function dotize($id)
     {
-        return strtolower(preg_replace('/[^\w]/i', '_', $id));
+        return strtolower(preg_replace('/\W/i', '_', $id));
     }
 
     /**
diff --git a/src/Symfony/Component/Filesystem/Tests/FilesystemTest.php b/src/Symfony/Component/Filesystem/Tests/FilesystemTest.php
index ad1a0928ab..62dfd9ad91 100644
--- a/src/Symfony/Component/Filesystem/Tests/FilesystemTest.php
+++ b/src/Symfony/Component/Filesystem/Tests/FilesystemTest.php
@@ -675,7 +675,7 @@ class FilesystemTest extends \PHPUnit_Framework_TestCase
      */
     public function testRenameThrowsExceptionOnError()
     {
-        $file = $this->workspace.DIRECTORY_SEPARATOR.uniqid();
+        $file = $this->workspace.DIRECTORY_SEPARATOR.uniqid('fs_test_', true);
         $newPath = $this->workspace.DIRECTORY_SEPARATOR.'new_file';
 
         $this->filesystem->rename($file, $newPath);
diff --git a/src/Symfony/Component/Finder/Tests/FinderTest.php b/src/Symfony/Component/Finder/Tests/FinderTest.php
index 3ae88a9db4..92f38ab94c 100644
--- a/src/Symfony/Component/Finder/Tests/FinderTest.php
+++ b/src/Symfony/Component/Finder/Tests/FinderTest.php
@@ -272,7 +272,7 @@ class FinderTest extends Iterator\RealIteratorTestCase
     public function testFilter($adapter)
     {
         $finder = $this->buildFinder($adapter);
-        $this->assertSame($finder, $finder->filter(function (\SplFileInfo $f) { return preg_match('/test/', $f) > 0; }));
+        $this->assertSame($finder, $finder->filter(function (\SplFileInfo $f) { return false !== strpos($f, 'test'); }));
         $this->assertIterator($this->toAbsolute(array('test.php', 'test.py')), $finder->in(self::$tmpDir)->getIterator());
     }
 
diff --git a/src/Symfony/Component/Finder/Tests/Iterator/CustomFilterIteratorTest.php b/src/Symfony/Component/Finder/Tests/Iterator/CustomFilterIteratorTest.php
index 62629b183f..b036ad13c2 100644
--- a/src/Symfony/Component/Finder/Tests/Iterator/CustomFilterIteratorTest.php
+++ b/src/Symfony/Component/Finder/Tests/Iterator/CustomFilterIteratorTest.php
@@ -39,7 +39,7 @@ class CustomFilterIteratorTest extends IteratorTestCase
     {
         return array(
             array(array(function (\SplFileInfo $fileinfo) { return false; }), array()),
-            array(array(function (\SplFileInfo $fileinfo) { return preg_match('/^test/', $fileinfo) > 0; }), array('test.php', 'test.py')),
+            array(array(function (\SplFileInfo $fileinfo) { return 0 === strpos($fileinfo, 'test'); }), array('test.php', 'test.py')),
             array(array('is_dir'), array()),
         );
     }
diff --git a/src/Symfony/Component/Finder/Tests/Iterator/MockSplFileInfo.php b/src/Symfony/Component/Finder/Tests/Iterator/MockSplFileInfo.php
index f2e8f8e2fd..a895350732 100644
--- a/src/Symfony/Component/Finder/Tests/Iterator/MockSplFileInfo.php
+++ b/src/Symfony/Component/Finder/Tests/Iterator/MockSplFileInfo.php
@@ -51,7 +51,7 @@ class MockSplFileInfo extends \SplFileInfo
     public function isFile()
     {
         if (null === $this->type) {
-            return preg_match('/file/', $this->getFilename());
+            return false !== strpos($this->getFilename(), 'file');
         };
 
         return self::TYPE_FILE === $this->type;
@@ -60,7 +60,7 @@ class MockSplFileInfo extends \SplFileInfo
     public function isDir()
     {
         if (null === $this->type) {
-            return preg_match('/directory/', $this->getFilename());
+            return false !== strpos($this->getFilename(), 'directory');
         }
 
         return self::TYPE_DIRECTORY === $this->type;
diff --git a/src/Symfony/Component/HttpFoundation/Session/Storage/MockArraySessionStorage.php b/src/Symfony/Component/HttpFoundation/Session/Storage/MockArraySessionStorage.php
index 96dae6b35c..f2d8bcf5a4 100644
--- a/src/Symfony/Component/HttpFoundation/Session/Storage/MockArraySessionStorage.php
+++ b/src/Symfony/Component/HttpFoundation/Session/Storage/MockArraySessionStorage.php
@@ -249,7 +249,7 @@ class MockArraySessionStorage implements SessionStorageInterface
      */
     protected function generateId()
     {
-        return sha1(uniqid(mt_rand()));
+        return sha1(uniqid('ss_mock_', true));
     }
 
     protected function loadSession()
diff --git a/src/Symfony/Component/HttpKernel/HttpCache/Esi.php b/src/Symfony/Component/HttpKernel/HttpCache/Esi.php
index 58b6265656..bc55bed51a 100644
--- a/src/Symfony/Component/HttpKernel/HttpCache/Esi.php
+++ b/src/Symfony/Component/HttpKernel/HttpCache/Esi.php
@@ -183,7 +183,7 @@ class Esi
             $chunks[$i] = sprintf('<?php echo $this->esi->handle($this, %s, %s, %s) ?>'."\n",
                 var_export($options['src'], true),
                 var_export(isset($options['alt']) ? $options['alt'] : '', true),
-                isset($options['onerror']) && 'continue' == $options['onerror'] ? 'true' : 'false'
+                isset($options['onerror']) && 'continue' === $options['onerror'] ? 'true' : 'false'
             );
             ++$i;
             $chunks[$i] = str_replace($this->phpEscapeMap[0], $this->phpEscapeMap[1], $chunks[$i]);
diff --git a/src/Symfony/Component/Process/ProcessUtils.php b/src/Symfony/Component/Process/ProcessUtils.php
index ed3dc35032..2ec608daa0 100644
--- a/src/Symfony/Component/Process/ProcessUtils.php
+++ b/src/Symfony/Component/Process/ProcessUtils.php
@@ -49,7 +49,7 @@ class ProcessUtils
 
             $escapedArgument = '';
             $quote = false;
-            foreach (preg_split('/(")/i', $argument, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE) as $part) {
+            foreach (preg_split('/(")/', $argument, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE) as $part) {
                 if ('"' === $part) {
                     $escapedArgument .= '\\"';
                 } elseif (self::isSurroundedBy($part, '%')) {
diff --git a/src/Symfony/Component/Process/Tests/PipeStdinInStdoutStdErrStreamSelect.php b/src/Symfony/Component/Process/Tests/PipeStdinInStdoutStdErrStreamSelect.php
index 89d1f6a1ac..26673ea45a 100644
--- a/src/Symfony/Component/Process/Tests/PipeStdinInStdoutStdErrStreamSelect.php
+++ b/src/Symfony/Component/Process/Tests/PipeStdinInStdoutStdErrStreamSelect.php
@@ -32,7 +32,7 @@ while ($read || $write) {
         }
         $out = (binary) substr($out, $written);
     }
-    if (null === $read && strlen($out) < 1) {
+    if (null === $read && '' === $out) {
         $write = array_diff($write, array(STDOUT));
     }
 
@@ -43,7 +43,7 @@ while ($read || $write) {
         }
         $err = (binary) substr($err, $written);
     }
-    if (null === $read && strlen($err) < 1) {
+    if (null === $read && '' === $err) {
         $write = array_diff($write, array(STDERR));
     }
 
diff --git a/src/Symfony/Component/Yaml/Inline.php b/src/Symfony/Component/Yaml/Inline.php
index 6d21a48f41..aff4ce7ff5 100644
--- a/src/Symfony/Component/Yaml/Inline.php
+++ b/src/Symfony/Component/Yaml/Inline.php
@@ -45,7 +45,7 @@ class Inline
 
         $value = trim($value);
 
-        if (0 == strlen($value)) {
+        if ('' === $value) {
             return '';
         }
 
diff --git a/src/Symfony/Component/Yaml/Parser.php b/src/Symfony/Component/Yaml/Parser.php
index ae4f500f7d..fc46ab3caf 100644
--- a/src/Symfony/Component/Yaml/Parser.php
+++ b/src/Symfony/Component/Yaml/Parser.php
@@ -509,9 +509,9 @@ class Parser
 
         // deal with trailing newlines as indicated
         if ('' === $indicator) {
-            $text = preg_replace('/\n+$/s', "\n", $text);
+            $text = preg_replace('/\n+$/', "\n", $text);
         } elseif ('-' === $indicator) {
-            $text = preg_replace('/\n+$/s', '', $text);
+            $text = preg_replace('/\n+$/', '', $text);
         }
 
         return $text;
@@ -610,7 +610,7 @@ class Parser
             $value = $trimmedValue;
 
             // remove end of the document marker (...)
-            $value = preg_replace('#\.\.\.\s*$#s', '', $value);
+            $value = preg_replace('#\.\.\.\s*$#', '', $value);
         }
 
         return $value;