help with preg_replace()

ive been tryin to find a solution for this problem for some hours now, but i just dont know how to do it... so i ask for ur assistance. Lemme list some examples, so u can see what im tryin to do :) "word" = "word" >word = >| word | <word = <| word | >"word = >|word | <word" = <| word| So if pattern is "word" it should stay "word", if patter is >"word it should replace it with >|word | and so on as u see from examples... any help or hints would be helpfull... thats what i have now: preg_replace("#^[<|>]?[^\"](.*?)[^\"]$#i", "| \\0 |", $string); .. but it doesnt work :P thx in advance !