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                    If we have the id for a post in <em>postid</em> and a limit of <em>num</em> and we want to find posts which share as many tags as possible with <em>postid</em>'s post, the following SQL will get you there.

SELECT p.*, COUNT(pt2.post_id) AS count FROM posts p, posts_tags pt, tags t, posts_tags pt2 WHERE pt.post_id=#{postid} AND = pt.tag_id AND pt2.post_id != pt.post_id AND pt2.tag_id=pt.tag_id AND = pt2.post_id GROUP BY pt2.post_id ORDER BY count DESC LIMIT #{num};")
                    Yet more code from Snippets itself. When you narrow down posts by tags, I only want you to see tags which are shared by other posts which also have the same current tags. This is more difficult than it sounds, and requires use of a subselect:

SELECT *, COUNT(pt.post_id) AS count FROM posts_tags pt, tags t WHERE pt.post_id IN (SELECT pt.post_id FROM posts_tags pt, tags t WHERE pt.tag_id = AND ( IN ('rails', 'ruby')) GROUP BY pt.post_id HAVING COUNT(pt.post_id)=2) AND = pt.tag_id GROUP BY pt.tag_id ORDER BY count DESC;
The first query (inside the subselect) finds all post IDs for posts which definitely contain any of the current tags. The outer query finds all OTHER tags associated with these posts, therefore we find all (and the quantity of) the tags related to the input tags.                
                    For some reason all the Apache docs tell you to run apxs over a .so file. I never had any .so files, but I found this to work (if you have the .c file for your module).

/usr/local/apache2/bin/apxs -c mod_foo.c
/usr/local/apache2/bin/apxs -i -a -n foo
It seems that the apxs compilation process puts the .so file in a folder called .libs/ which is invisible to a regular ls, but the above works too.                
                    If you have three tables, 'posts', 'tags', and a join table 'posts_tags', and you wish to find all posts which are all associated with a number of different tags, you can use this SQL trick:

SELECT p.* FROM posts_tags pt, posts p, tags t WHERE pt.tag_id = AND ( IN ('tag1', 'tag2', 'tag3')) AND GROUP BY HAVING COUNT( = 3;
.. where 3 is the number of tags in total. In Ruby/Rails, if you have an array called 'tags' containing the tags, you could use this code:

@posts = Post.find_by_sql ("SELECT p.* FROM posts_tags pt, posts p, tags t WHERE pt.tag_id = AND ( = '" + tags.uniq.join ('\' OR\'') + "') AND GROUP BY HAVING COUNT( = " + tags.uniq.length.to_s)

This is how Snippets itself works. You can also add a p.user_id check to the HAVING operator to only find posts with certain tags by a certain user.                
                    Tobi posted this as a new URL scheme for Typo.

# allow neat perma urls
map.connect 'articles/:year/:month/:day', :controller  => 'articles', 
     :action => 'find_by_date', 
     :year => /\d{4}/, :day => nil, :month => nil
map.connect 'articles/:year/:month/:day/:title', :controller  => 'articles', 
     :action => 'permalink', :year => /\d{4}/
                    Run as root:

#Software suspend
echo 4 > /proc/acpi/sleep

#umount and mount all devices
umount -a -r
mount -a
                    Looking up the length of an array on each iteration of a loop is slow and inefficient (if the length of the array isn't changing).

If it's OK to iterate from back to front:
for ( var i=myArray.length-1; i>=0; --i ){

If you need to go from front to back:
for ( var i=0, len=myArray.length; i<len; ++i ){
Math.randomMax = function(maxVal,asFloat){
	var val = Math.random()*maxVal;
	return asFloat?val:Math.round(val);

For a random integer between 0 and 10 (inclusive), simply:
var theNumber = Math.randomMax( 10 );

For a random float value between 0 and 10, pass a truth value to the second parameter:
var theNumber = Math.randomMax( 10, true );
/usr/sbin/ioreg -p IODeviceTree -n battery -w 0 | grep IOBatteryInfo

ioreg -l -w0 | grep -i IOBatteryInfo
@params[:tags].map do |tag|
	Tag.find_by_name (tag) rescue nil