diff --git a/src/ContainerProvider.php b/src/ContainerProvider.php
index d37dad9..0f4b533 100644
--- a/src/ContainerProvider.php
+++ b/src/ContainerProvider.php
@@ -45,6 +45,7 @@ public function __construct(
             Method\Command\GnuGzip::getClass(),
             Method\Command\GnuTar::getClass(),
             Method\Command\Unrar::getClass(),
+            Method\Command\Unshar::getClass(),
             Method\Command\Unzip::getClass(),
             Method\Command\x7zip::getClass(),
             Method\Command\Xz::getClass(),
diff --git a/src/Format/Simple/Cpio.php b/src/Format/Simple/Cpio.php
index 6b56902..19a8ed3 100644
--- a/src/Format/Simple/Cpio.php
+++ b/src/Format/Simple/Cpio.php
@@ -21,7 +21,7 @@ class Cpio extends AbstractFormat
      */
     public function getCompressionRatioLevel()
     {
-        return FormatInterface::RATIO_LEVEL_MIDDLE;
+        return FormatInterface::RATIO_LEVEL_LOWEST;
     }
 
     /**
diff --git a/src/Format/Simple/Shar.php b/src/Format/Simple/Shar.php
index ed02489..5870601 100644
--- a/src/Format/Simple/Shar.php
+++ b/src/Format/Simple/Shar.php
@@ -21,7 +21,7 @@ class Shar extends AbstractFormat
      */
     public function getCompressionRatioLevel()
     {
-        return FormatInterface::RATIO_LEVEL_MIDDLE;
+        return FormatInterface::RATIO_LEVEL_LOWEST;
     }
 
     /**
diff --git a/src/Method/Command/Unshar.php b/src/Method/Command/Unshar.php
new file mode 100644
index 0000000..c281a60
--- /dev/null
+++ b/src/Method/Command/Unshar.php
@@ -0,0 +1,68 @@
+<?php
+
+/*
+ * This file is part of the Distill package.
+ *
+ * (c) Raul Fraile <raulfraile@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Distill\Method\Command;
+
+use Distill\Exception;
+use Distill\Format;
+
+/**
+ * Extracts files from shar archives.
+ *
+ * @author Raul Fraile <raulfraile@gmail.com>
+ */
+class Unshar extends AbstractCommandMethod
+{
+
+    /**
+     * {@inheritdoc}
+     */
+    public function extract($file, $target, Format\FormatInterface $format)
+    {
+        $this->checkSupport($format);
+
+        $this->getFilesystem()->mkdir($target);
+
+        $command = sprintf('cd %s && sh %s', escapeshellarg($target), escapeshellarg($file));
+
+        $exitCode = $this->executeCommand($command);
+
+        return $this->isExitCodeSuccessful($exitCode);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isSupported()
+    {
+        if (null === $this->supported) {
+            $this->supported = $this->existsCommand('sh');
+        }
+
+        return $this->supported;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function getClass()
+    {
+        return get_class();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function isFormatSupported(Format\FormatInterface $format = null)
+    {
+        return $format instanceof Format\Simple\Shar;
+    }
+}
diff --git a/tests/Format/Simple/SharTest.php b/tests/Format/Simple/SharTest.php
new file mode 100644
index 0000000..508e23b
--- /dev/null
+++ b/tests/Format/Simple/SharTest.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Distill\Tests\Format\Simple;
+
+use Distill\Format\Simple\Shar;
+use Distill\Tests\Format\AbstractFormatTest;
+
+class SharTest extends AbstractFormatTest
+{
+    public function setUp()
+    {
+        $this->format = new Shar();
+    }
+
+    public function testCompressionRatioLevelIsValid()
+    {
+        $this->assertLevelValid($this->format->getCompressionRatioLevel());
+    }
+}
diff --git a/tests/Method/Command/UnsharTest.php b/tests/Method/Command/UnsharTest.php
new file mode 100644
index 0000000..49ef826
--- /dev/null
+++ b/tests/Method/Command/UnsharTest.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace Distill\Tests\Method\Command;
+
+use Distill\Method;
+use Distill\Format;
+use Distill\Tests\Method\AbstractMethodTest;
+
+class UnsharTest extends AbstractMethodTest
+{
+    public function setUp()
+    {
+        $this->method = new Method\Command\Unshar();
+
+        if (false === $this->method->isSupported()) {
+            $this->markTestSkipped('The unshar command is not installed');
+        }
+
+        parent::setUp();
+    }
+
+    public function testExtractCorrectSharFile()
+    {
+        $target = $this->getTemporaryPath();
+        $this->clearTemporaryPath();
+
+        $response = $this->extract('file_ok.shar', $target, new Format\Simple\Shar());
+
+        $this->assertTrue($response);
+        $this->assertUncompressed($target, 'file_ok.shar');
+        $this->clearTemporaryPath();
+    }
+
+}
diff --git a/tests/Resources/files/file_fake.shar b/tests/Resources/files/file_fake.shar
new file mode 100644
index 0000000..fc15c24
Binary files /dev/null and b/tests/Resources/files/file_fake.shar differ
diff --git a/tests/Resources/files/file_ok.shar b/tests/Resources/files/file_ok.shar
new file mode 100644
index 0000000..13ba38b
--- /dev/null
+++ b/tests/Resources/files/file_ok.shar
@@ -0,0 +1,25 @@
+# This is a shell archive.  Save it in a file, remove anything before
+# this line, and then unpack it by entering "sh file".  Note, it may
+# create directories; files and directories will be owned by you and
+# have default permissions.
+#
+# This archive contains:
+#
+#	1.txt
+#	2.txt
+#	3.txt
+#
+echo x - 1.txt
+sed 's/^X//' >1.txt << 'END-of-1.txt'
+X1.txt file
+END-of-1.txt
+echo x - 2.txt
+sed 's/^X//' >2.txt << 'END-of-2.txt'
+X2.txt file
+END-of-2.txt
+echo x - 3.txt
+sed 's/^X//' >3.txt << 'END-of-3.txt'
+X3.txt file
+END-of-3.txt
+exit
+
diff --git a/tests/Resources/files/file_ok.shar.key b/tests/Resources/files/file_ok.shar.key
new file mode 100644
index 0000000..0f0245c
--- /dev/null
+++ b/tests/Resources/files/file_ok.shar.key
@@ -0,0 +1,3 @@
+/1.txt|1.txt file
+/2.txt|2.txt file
+/3.txt|3.txt file
\ No newline at end of file
diff --git a/tests/Resources/scripts/main.sh b/tests/Resources/scripts/main.sh
index 9dfcfa8..7950c66 100755
--- a/tests/Resources/scripts/main.sh
+++ b/tests/Resources/scripts/main.sh
@@ -30,4 +30,6 @@ $DIR/epub.sh
 $DIR/jar.sh
 $DIR/dmg.sh
 $DIR/iso.sh
-$DIR/ar+deb.sh
\ No newline at end of file
+$DIR/ar+deb.sh
+$DIR/cpio.sh
+$DIR/shar.sh
\ No newline at end of file
diff --git a/tests/Resources/scripts/shar.sh b/tests/Resources/scripts/shar.sh
new file mode 100755
index 0000000..666deff
--- /dev/null
+++ b/tests/Resources/scripts/shar.sh
@@ -0,0 +1,24 @@
+#!/bin/bash
+
+################################################################################
+# Initial configuration
+################################################################################
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+FILES_DIR="$DIR/../files"
+
+################################################################################
+# Clean files
+################################################################################
+rm -f $FILES_DIR/file_ok.shar $FILES_DIR/file_fake.shar
+
+################################################################################
+# Generate files
+################################################################################
+
+# shar: fake file
+dd if=/dev/urandom of=$FILES_DIR/file_fake.shar bs=1 count=1240
+
+# shar: regular file
+cd $FILES_DIR/uncompressed
+shar 1.txt 2.txt 3.txt > ../file_ok.shar
+printf "\1.txt|1.txt file\n\2.txt|2.txt file\n\3.txt|3.txt file" > ../file_ok.shar.key