The minus sign (-) in ranges selects a single line that is a specified
 number of lines before a specified line.

 Format: [range] - [n]

 Range is a single line range, and n is an integer.  The line selected is
 the line that is n lines before the line specified by range.  If you
 omit range, the current line is used; if you omit n, 1 is used.

 Ex: TYPE 15 - 3     Display the third line before the line numbered 15.

     TYPE END -1     Display the last line in the buffer.

     TYPE -          Display the previous line.