All the text windows, will initialize in "input" mode (standard cocoa text input). You invoke the Vi-command window (exit the input mode) by hitting ` (the back-apostrophe key, this is customizable, see installation instructions) and then key in your favorite Vi commands. For example, move down a line 'j', move right 'l', delete two lines 'd2d', and so on. You enter back into "input" mode by typing the 'i'. You get the idea. Right now, you should be thinking -- "you mean the editor in XCode will behave like Vi?" Answer: Yes.