49:  Is there an equivalent to the `.' (dot) command of vi?

  (`.' is the redo command in vi.  It redoes the last insertion/deletion.)

  No, not really, because Emacs doesn't have a special insertion mode.

  You can type "C-x ESC ESC" (repeat-complex-command) to reinvoke commands
  that used the minibuffer to get arguments.  In repeat-complex-command you
  can type M-p and M-n to scan through all the different complex commands
  you've typed.

  To repeat a set of commands, use keyboard macros.  (See "Keyboard Macros"
  in the on-line manual.)

  If you're really desperate for the `.' command, vip-mode, which comes
  with Emacs 19, appears to support it.  (Vi-mode, another vi emulator that
  comes with Emacs 19, does not appear to support `.'.)