Marks current position with x (x can be any letter).
(apostrophe) Moves cursor to first character of line marked by x.
(backquote) Moves cursor to character marked by x.
(backquotes) Returns to exact position of previous mark or context after a move.
(apostrophes) Returns to the beginning of the line of the previous mark or context. Place markers are set only during the current vi session; they are not stored in the file.