Select:
    F - File functions: load, save, rename, discard
    B - Select buffer, 0-7
    S - Text search/replace; goto a line
    M - Mark blocks, copy, move, delete, print
    D - Go to DOS prompt; 'exit' command returns to editor
    Q - Quit SBE
    O - Other, miscellaneous functions: tabs, key click, color, parameter save

    ESC - return to edit mode
