EmuCON is a small and nice command-line interpreter for any Atari computer (similar to Mupfell, TomShell, etc.) . It features command-line history, TAB completion, and more. It is the easiest way to run TTP programs without having to retype the whole command line for each run.
EmuCON has always been embedded into EmuTOS, now it is also available as standalone executable. Go to the EmuTOS download page
and get emucon-*.zip from there.