Displaying posts from a selected category only

How to display (by modifying a theme)开发者_如何学运维 posts from a certain category only instead of showing them all?

this should work

<?php query_posts('cat=1'); ?>
<?php while (have_posts()) : the_post(); ?>
  <!-- post's contents -->
<?php endwhile; ?>

The answers you seek lie in the Wordpress documentation. It's there if you look for more than 2 seconds: http://codex.wordpress.org/The_Loop#Loop_Examples

In its simplest form:

$query = new WP_Query( 'category_name=foo' );