If no start is entered, the last ten lines of the file are displayed. 'tail -r file' displays 'file' with the lines is reverse order. To display the last ten lines in reverse order, enter 'tail -10r file'. My recommendation for 'pg' is to use either 'more' or 'less'. Enter 'q' to quit 'less'. If you are a Unix Superuser, consider using 'less'.
Detailed options are available by entering 'man less' or, from within 'less', 'h'.
A common use of paging programs is in combination with another command and a pipeline to prevent scrolling off the screen. On System V Unix, it is 'lp'. The 'lpr' command causes Unix to make a temporary copy of the file and save it to a special directory. It then adds the print job to a print queue. Once the print job is finished, the temporary file is removed.