import os ## for os.path.isfile()
def dealline(line) :
    print(line) ##  for line I can do a lot of things
def getfilename() :
    return input('Please input file name(input exit() for exit):').strip()
class more : ## MORE function
    linenum = 0
    size = 10
    def work(self) :
        if self.linenum >= self.size :
            if input('--MORE--').strip().lower() == 'exit()' :
                return False
            self.linenum = 0
        else :
            self.linenum += 1
        return True
while True :
    try :
        filename = getfilename()
        if filename.lower() == 'exit()' : ##  exit
            break
        if os.path.isfile(filename) : ##  Determine if the file exists
            f = open(filename)
            try :
                lines = f.readlines()
                m = more()
                for line in lines:
                    if False == m.work() :
                        break
                    dealline(line)

                ## input()
            finally :
                f.close()
        else :
            print('File does not exists.')
            ##input()
    except :
        print('Input Error!')

You can also use

with open(filename) as fh:
    for line in fh:
        yield line

Output each line