[Izkata]

I don't know how consistent this is across shells, but at least in bash putting a space before the command keeps it out of the history:

  $ ONE=1
  $  TWO=2
  $ echo $ONE $TWO
  1 2
  $ history | tail -n 4
   2002  clear
   2003  ONE=1
   2004  echo $ONE $TWO
   2005  history | tail -n 4

[johnisgood]

Yeah, I have been using this feature of bash ever since its existence and it is quite handy at times, especially when I do "printf "<sensitive data>" | qr".