With the launch of WordPress 3.6 Twenty Thirteen is the default theme, its much responsive than the older one and feature rich with vibrant colors. By default in Twenty Thirteen displays full posts in home page, category, tag, author and archive pages except search results page.
By displaying excerpts in home page you can achieve a neat look on your blog and also it reduces the loading time by showing a short summary of your posts. This can be achieved by using a simple code in content.php.
Before making any changes on any theme take a backup of your theme so that you will not lose the theme if you make the changes in wrong way.
Open content.php from c-panel which is located at /wp-content/themes/twentythirteen/ or you can directly access this file from WordPress dashboard
Goto Appearence [icon name=”icon-angle-right”] Editor [icon name=”icon-angle-right”] content.php.
Find the below line
<?php if ( is_search() ) : // Only display Excerpts for Search ?>
Change it with below piece of code
<?php if ( is_search() || is_author() || is_tag() || is_archive() || is_home () ) : ?>
Save content.php and refresh your site. You should see posts displayed as excerpts. If you don’t want to show excerpts in author page just remove is_author() || from the above code.
Hope this tutorial helps you, if you have any doubts feel free to comment here.