Append new text at specified
address, or at present address if none is specified. Add a
! to switch the autoindent setting that will be used during input (e.g., if autoindent is enabled,
! disables it). Enter new text after entering the command. Terminate input of new text by entering a line consisting of just a period.
:a Begin appending to current line Append this line and this line too. . Terminate input of text to append