During a vi session, you can mark your place in the file with an invisible "bookmark," perform edits elsewhere, then return to your marked place. In command mode:
mxMarks current position with x (x can be any letter).
'x(apostrophe) Moves cursor to first character of line marked by x.
`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.