Create a simple Portfolio Custom Post Type

functions.php

<?php

// Create portfolio custom post type

add_action( 'init', 'register_cpt_portfolio' );

function register_cpt_portfolio() {
  register_post_type( 'portfolio',
		array(
			'labels' => array(
				'name' => __( 'Portfolio', 'portfolio' ),
				'singular_name' => __( 'Portfolio', 'portfolio' ),
			),
			'exclude_from_search' => true,
			'has_archive' => true,
			'hierarchical' => true,
			'public' => true,
			'rewrite' => array( 'slug' => 'portfolio' ),
			'supports' => array( 'title', 'editor', 'author', 'thumbnail', 'excerpt', 'trackbacks', 'custom-fields', 'comments', 'revisions', 'page-attributes' ),
		)
	);
}