1: program trutst 2: integer ftell 3: external ftell 4: 5: rewind 1 6: write(1,*) "This is line A." 7: write(1,*) "This is line B." 8: write(1,*) "This is line C." 9: write(1,*) "This is line D." 10: backspace 1 11: endfile 1 12: call system ("cat fort.1") 13: write(*,*) "---" 14: rewind 1 15: write(1,*) "This is line E." 16: write(1,*) "This is line F." 17: close(1) 18: call system ("cat fort.1") 19: end