program trutst
	integer ftell
	external ftell

	rewind 1
	write(1,*) "This is line A."
	write(1,*) "This is line B."
	write(1,*) "This is line C."
	write(1,*) "This is line D."
	backspace 1
	endfile 1
	call system ("cat fort.1")
	write(*,*) "---"
	rewind 1
	write(1,*) "This is line E."
	write(1,*) "This is line F."
	close(1)
	call system ("cat fort.1")
	end