Add 'php' format to produce serialized output.

src/FormatterManager.php

@@ -18,6 +18,7 @@ public function __construct()
             'yaml' => '\Consolidation\OutputFormatters\Formatters\YamlFormatter',
             'json' => '\Consolidation\OutputFormatters\Formatters\JsonFormatter',
             'print-r' => '\Consolidation\OutputFormatters\Formatters\PrintRFormatter',
+            'php' => '\Consolidation\OutputFormatters\Formatters\SerializeFormatter',
             'var_export' => '\Consolidation\OutputFormatters\Formatters\VarExportFormatter',
             'list' => '\Consolidation\OutputFormatters\Formatters\ListFormatter',
             'csv' => '\Consolidation\OutputFormatters\Formatters\CsvFormatter',

src/Formatters/SerializeFormatter.php

@@ -0,0 +1,16 @@
+<?php
+namespace Consolidation\OutputFormatters\Formatters;
+
+use Consolidation\OutputFormatters\FormatterInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class SerializeFormatter implements FormatterInterface
+{
+    /**
+     * @inheritdoc
+     */
+    public function write(OutputInterface $output, $data, $options = [])
+    {
+        $output->writeln(serialize($data));
+    }
+}

tests/testFormatters.php

@@ -95,6 +95,19 @@ function testSimpleJson()
         $this->assertFormattedOutputMatches($expected, 'json', $data);
     }
 
+    function testSerializeFormat()
+    {
+        $data = [
+            'one' => 'a',
+            'two' => 'b',
+            'three' => 'c',
+        ];
+
+        $expected = 'a:3:{s:3:"one";s:1:"a";s:3:"two";s:1:"b";s:5:"three";s:1:"c";}';
+
+        $this->assertFormattedOutputMatches($expected, 'php', $data);
+    }
+
     function testNestedJson()
     {
         $data = [