text: what is the difference of "but" and " , but" (comma)? i dont know, any1 who is good at  grammar? ", but" with a comma us used as a conjunction linking 2 parts of a sentence. (ex. we would go to the store, but i'm broke.)  "but" w/o a comma could be used for other things like saying 'except for'. (ex. we have all but one of our pencils that we need.)  mostly though, the word but is used as the conjunction.