I write in a code editor. I spend so much time in a code editor that I've gotten to the point where I just feel more comfortable using that than something like Word. I haven't used Word much in a long time, either, and I don't want to get bogged down with formatting and whatnot. Frankly, I don't write enough for me to feel it's worthwhile to learn a new program.
As far as how I write, I can't start at the beginning and just write until the story is over. I can't let a story meander, either. I'm great at coming up with interesting premises and interesting scenes, but I'm terrible at coming up with a good ending. I need to have a whole story arc and an ending I like before I'm willing to put forth the effort of writing the middle.
I generally write notes on the overall plot and bits of scenes as I let the story stew. I tend write the beginning and the end, not necessarily in that order, before I really tackle the middle. Then I keep going back to what I've already written to make sure that it still matches with the new stuff. It's not a linear process at all.
I can't imagine starting a story in earnest without knowing where it's going. I also can't imagine, even starting with an outline, writing a chapter, posting it, then writing another one. I admire those who can an can still make a coherent story. I'm too likely to change things downstream and decide that I didn't want to have so-and-so say such-and-such back in chapter 1 because now it conflicts with something in a later chapter. I end up tweaking things throughout a story as I add new sections, though once I'm happy with a section I generally leave it alone.
