starbeam

I am not sure what I need to do for this. I am trying to write a program that uses the tail command from Unix in windows. I am trying to get it to go to the bottom of the file and then print out however many lines that the user puts in from the bottom. I have got it where it opens a text file and I can get it to go to the bottom of the file using
but I dont know how to get it to go back to the start of that line and print it out and then keep going back until it gets to the number of lines that the user wanted printed. I know that a loop will have to be used. I was thinking a for loop but I just dont know how to get my program the go back to the start of that line once I get it to go to the bottom of the text file.