Really simple regex

Now, I know that this is easy, but I am embarassed to say that I can't find a regex tutorial that will show me how to match any occurances of x and replace them with one x: xxxxx >x xx > x x > x $string="I have xxxxxxxx apples!"; $string=preg_replace("-regex here-","x", $string); print "$string"; I have x apples! I searched marc because I know that I've seen this, but I don't know on what keywords to search. I know that php uses perl-compatable regular expressions, but in no tutorial did I find this. I know that * matches any amount of occurances of a string, but formulating it to do it in the middle of a string of text I could not get. Dotan http://lyricslist.com/lyrics/artist_albums/19/adams_bryan.php Bryan Adams Lyrics