content filter

add_filter('the_content', 'alc_autoshort_content');
//a filter to turn the content of posts without the more-tag into excerpts///alchymyth 10/2011//
function alc_autoshort_content( $content ) {
    if( !is_singular() ) : // don't do it for single posts and pages
    global $post;
    if(!strpos($post->post_content,'<!--more')) {
    // check for the 'more-tag' and leave posts with 'more-tag' unchanged
        $text = do_shortcode( $content ); // otherwise make an excerpt
        $text = strip_tags($text);
        $excerpt_length = apply_filters('excerpt_length', 55);
        $excerpt_more = apply_filters('excerpt_more', ' ' . '[...]');
        $words = explode(' ', $text, $excerpt_length + 1);
        if (count($words)> $excerpt_length) {
            array_pop($words);
            $text = implode(' ', $words);
            $text = $text . $excerpt_more;
            // add the [...] or a possible link at the end of the shortened post
        } else {
            $text = implode(' ', $words) . $excerpt_more;
            // add [...] or possible link even at the end of a short post
        }
        $content = $text;
    }
    endif;
return $content;
}