gistfile1.php

add_action('admin_notices','themeslug_import_settings');
function themeslug_import_settings()
{
	
	global $pagenow;
	if ( is_admin() && $pagenow == "themes.php" && isset( $_GET['activated'] ) ) {
		?>
		<div class="updated below-h2">
			<p style="font-size: 18px;">
				<?php _e('<strong>You\'re almost done!</strong> To import settings for this theme,');?> <a href="<?php echo admin_url('themes.php');?>?slug=installchild"><?php _e('click here','generate');?></a>.
			</p>
		</div>
		<?php
	}
	if ( is_admin() && $pagenow == 'themes.php' &&	isset( $_GET['slug'] ) ) {
		if ($_GET['slug'] == 'installchild') {
		?>
			<div class="updated below-h2">
				<p>
					<?php _e('Child theme successfully installed.','generate'); ?>
				</p>
			</div>
		<?php
			$rawdata = file_get_contents(esc_url( 'http://url-to/settings.dat' ));
			$import  = unserialize($rawdata);
			foreach ($import as $key => $item) {
				update_option($key, $item);
			}
		}
	}
}