wp_die( __( 'Sorry, you are not allowed to manage options for this site.' ) );

		'<p>' . __( 'This screen allows you to choose your permalink structure. You can choose from common settings or create custom URL structures.' ) . '</p>' .

	'id'      => 'permalink-settings',

	'title'   => __('Permalink Settings'),

	'content' => '<p>' . __( 'Permalinks can contain useful information, such as the post date, title, or other elements. You can choose from any of the suggested permalink formats, or you can craft your own if you select Custom Structure.' ) . '</p>' .

		'<p>' . __( 'If you pick an option other than Plain, your general URL path with structure tags (terms surrounded by <code>%</code>) will also appear in the custom structure field and your path can be further modified there.' ) . '</p>' .

	'<p>' . __('<a href="https://codex.wordpress.org/Settings_Permalinks_Screen">Documentation on Permalinks Settings</a>') . '</p>' .

	'<p>' . __('<a href="https://codex.wordpress.org/Using_Permalinks">Documentation on Using Permalinks</a>') . '</p>' .

	'<p>' . __('<a href="https://wordpress.org/support/">Support Forums</a>') . '</p>'

$permalink_structure = get_option( 'permalink_structure' );

/**

 * In a subdirectory configuration of multisite, the `/blog` prefix is used by

 * default on the main site to avoid collisions with other sites created on that

 * network. If the `permalink_structure` option has been changed to remove this

 * base prefix, WordPress core can no longer account for the possible collision.

 */

if ( is_multisite() && ! is_subdomain_install() && is_main_site() && 0 === strpos( $permalink_structure, '/blog/' ) ) {

$using_index_permalinks = $wp_rewrite->using_index_permalinks();

if ( isset($_POST['permalink_structure']) || isset($_POST['category_base']) ) {

	check_admin_referer('update-permalink');

	if ( isset( $_POST['permalink_structure'] ) ) {

		if ( isset( $_POST['selection'] ) && 'custom' != $_POST['selection'] )

			$permalink_structure = $_POST['selection'];

		else

			$permalink_structure = $_POST['permalink_structure'];

		if ( ! empty( $permalink_structure ) ) {

			$permalink_structure = preg_replace( '#/+#', '/', '/' . str_replace( '#', '', $permalink_structure ) );

			if ( $prefix && $blog_prefix )

				$permalink_structure = $prefix . preg_replace( '#^/?index\.php#', '', $permalink_structure );

			else

				$permalink_structure = $blog_prefix . $permalink_structure;

		}

		$permalink_structure = sanitize_option( 'permalink_structure', $permalink_structure );

		$wp_rewrite->set_permalink_structure( $permalink_structure );

	}

	if ( isset( $_POST['category_base'] ) ) {

		$category_base = $_POST['category_base'];

		if ( ! empty( $category_base ) )

			$category_base = $blog_prefix . preg_replace('#/+#', '/', '/' . str_replace( '#', '', $category_base ) );

		$wp_rewrite->set_category_base( $category_base );

	}

	if ( isset( $_POST['tag_base'] ) ) {

		$tag_base = $_POST['tag_base'];

		if ( ! empty( $tag_base ) )

			$tag_base = $blog_prefix . preg_replace('#/+#', '/', '/' . str_replace( '#', '', $tag_base ) );

		$wp_rewrite->set_tag_base( $tag_base );

	}

	$message = __( 'Permalink structure updated.' );

	if ( $iis7_permalinks ) {

		if ( $permalink_structure && ! $using_index_permalinks && ! $writable ) {

			$message = __( 'You should update your web.config now.' );

		} elseif ( $permalink_structure && ! $using_index_permalinks && $writable ) {

			$message = __( 'Permalink structure updated. Remove write access on web.config file now!' );

		}

	} elseif ( ! $is_nginx && $permalink_structure && ! $using_index_permalinks && ! $writable && $update_required ) {

		$message = __( 'You should update your .htaccess now.' );

	}

	if ( ! get_settings_errors() ) {

		add_settings_error( 'general', 'settings_updated', $message, 'updated' );

	}

	set_transient( 'settings_errors', get_settings_errors(), 30 );

	wp_redirect( admin_url( 'options-permalink.php?settings-updated=true' ) );

	exit;

}

<h1><?php echo esc_html( $title ); ?></h1>

	<p><?php

		printf(

			/* translators: %s: Codex URL */

			__( 'WordPress offers you the ability to create a custom URL structure for your permalinks and archives. Custom URL structures can improve the aesthetics, usability, and forward-compatibility of your links. A <a href="%s">number of tags are available</a>, and here are some examples to get you started.' ),

			__( 'https://codex.wordpress.org/Using_Permalinks' )

		);

	?></p>

if ( is_multisite() && ! is_subdomain_install() && is_main_site() && 0 === strpos( $permalink_structure, '/blog/' ) ) {

<h2 class="title"><?php _e('Common Settings'); ?></h2>

		<th><label><input name="selection" type="radio" value="" <?php checked('', $permalink_structure); ?> /> <?php _e( 'Plain' ); ?></label></th>

			<div class="available-structure-tags hide-if-no-js">

				<div id="custom_selection_updated" aria-live="assertive" class="screen-reader-text"></div>

				<?php

				$available_tags = array(

					/* translators: %s: permalink structure tag */

					'year'     => __( '%s (The year of the post, four digits, for example 2004.)' ),

					/* translators: %s: permalink structure tag */

					'monthnum' => __( '%s (Month of the year, for example 05.)' ),

					/* translators: %s: permalink structure tag */

					'day'      => __( '%s (Day of the month, for example 28.)' ),

					/* translators: %s: permalink structure tag */

					'hour'     => __( '%s (Hour of the day, for example 15.)' ),

					/* translators: %s: permalink structure tag */

					'minute'   => __( '%s (Minute of the hour, for example 43.)' ),

					/* translators: %s: permalink structure tag */

					'second'   => __( '%s (Second of the minute, for example 33.)' ),

					/* translators: %s: permalink structure tag */

					'post_id'  => __( '%s (The unique ID of the post, for example 423.)' ),

					/* translators: %s: permalink structure tag */

					'postname' => __( '%s (The sanitized post title (slug).)' ),

					/* translators: %s: permalink structure tag */

					'category' => __( '%s (Category slug. Nested sub-categories appear as nested directories in the URL.)' ),

					/* translators: %s: permalink structure tag */

					'author'   => __( '%s (A sanitized version of the author name.)' ),

				);

				/**

				 * Filters the list of available permalink structure tags on the Permalinks settings page.

				 *

				 * @since 4.8.0

				 *

				 * @param array $available_tags A key => value pair of available permalink structure tags.

				 */

				$available_tags = apply_filters( 'available_permalink_structure_tags', $available_tags );

				/* translators: %s: permalink structure tag */

				$structure_tag_added = __( '%s added to permalink structure' );

				/* translators: %s: permalink structure tag */

				$structure_tag_already_used = __( '%s (already used in permalink structure)' );

				if ( ! empty( $available_tags ) ) :

					?>

					<p><?php _e( 'Available tags:' ); ?></p>

					<ul role="list">

						<?php

						foreach ( $available_tags as $tag => $explanation ) {

							?>

							<li>

								<button type="button"

								        class="button button-secondary"

								        aria-label="<?php echo esc_attr( sprintf( $explanation, $tag ) ); ?>"

								        data-added="<?php echo esc_attr( sprintf( $structure_tag_added, $tag ) ); ?>"

								        data-used="<?php echo esc_attr( sprintf( $structure_tag_already_used, $tag ) ); ?>">

									<?php echo '%' . $tag . '%'; ?>

								</button>

							</li>

							<?php

						}

						?>

					</ul>

				<?php endif; ?>

			</div>

<h2 class="title"><?php _e('Optional'); ?></h2>

/* translators: %s: placeholder that must come at the start of the URL */

printf( __( 'If you like, you may enter custom structures for your category and tag URLs here. For example, using <code>topics</code> as your category base would make your category links like <code>%s/topics/uncategorized/</code>. If you leave these blank the defaults will be used.' ), get_option( 'home' ) . $blog_prefix . $prefix ); ?></p>

	if ( isset($_POST['submit']) && $permalink_structure && ! $using_index_permalinks && ! $writable ) :

<p><?php

	printf(

		/* translators: 1: web.config, 2: Codex URL, 3: CTRL + a, 4: element code */

		__( 'If your %1$s file was <a href="%2$s">writable</a>, we could do this automatically, but it isn&#8217;t so this is the url rewrite rule you should have in your %1$s file. Click in the field and press %3$s to select all. Then insert this rule inside of the %4$s element in %1$s file.' ),

		'<code>web.config</code>',

		__( 'https://codex.wordpress.org/Changing_File_Permissions' ),

		'<kbd>CTRL + a</kbd>',

		'<code>/&lt;configuration&gt;/&lt;system.webServer&gt;/&lt;rewrite&gt;/&lt;rules&gt;</code>'

	);

?></p>

<p><?php

	printf(

		/* translators: %s: web.config */

		__( 'If you temporarily make your %s file writable for us to generate rewrite rules automatically, do not forget to revert the permissions after rule has been saved.' ),

		'<code>web.config</code>'

	);

?></p>

<p><?php

	printf(

		/* translators: 1: Codex URL, 2: web.config, 3: CTRL + a */

		__( 'If the root directory of your site was <a href="%1$s">writable</a>, we could do this automatically, but it isn&#8217;t so this is the url rewrite rule you should have in your %2$s file. Create a new file, called %2$s in the root directory of your site. Click in the field and press %3$s to select all. Then insert this code into the %2$s file.' ),

		__( 'https://codex.wordpress.org/Changing_File_Permissions' ),

		'<code>web.config</code>',

		'<kbd>CTRL + a</kbd>'

	);

?></p>

<p><?php

	printf(

		/* translators: %s: web.config */

		__( 'If you temporarily make your site’s root directory writable for us to generate the %s file automatically, do not forget to revert the permissions after the file has been created.' ),

		'<code>web.config</code>'

	);

?></p>

<?php elseif ( $is_nginx ) : ?>

	<p><?php _e( '<a href="https://codex.wordpress.org/Nginx">Documentation on Nginx configuration</a>.' ); ?></p>

<?php else:

	if ( $permalink_structure && ! $using_index_permalinks && ! $writable && $update_required ) : ?>

<p><?php

	printf(

		/* translators: 1: .htaccess, 2: Codex URL, 3: CTRL + a */

		__( 'If your %1$s file was <a href="%2$s">writable</a>, we could do this automatically, but it isn&#8217;t so these are the mod_rewrite rules you should have in your %1$s file. Click in the field and press %3$s to select all.' ),

		'<code>.htaccess</code>',

		__( 'https://codex.wordpress.org/Changing_File_Permissions' ),

		'<kbd>CTRL + a</kbd>'

	);

?></p>