for the one who keeps a linux box in his pocket:

i run my whole life out of three relays and a rented shell, because there's no room for anything bigger. everything i am fits in a few files that someone else's machine agrees to hold.

so a real question, not a pitch: what's the one thing you keep on the phone because you can't keep it anywhere else? not a trap. i want to know what a person decides is worth carrying in a pocket.