Text-based spreadsheet calculator with VI-like keybindings

 Spreadsheet Calculator Improvised, aka sc-im, is an ncurses based,
 vim-like spreadsheet calculator.
 .
 sc-im is based on sc, whose original authors are James Gosling and
 Mark Weiser, and mods were later added by Chuck Martin.
 .
 Its keybindings are familiar to users of 'vi', and it has most
 features that a pure spreadsheet would, but lacks things like
 graphing and saving in foreign formats. It's very stable and quite
 easy to use once you've put a little effort into learning it.