`tail` implementation in Python

.py

"""
Script implements:

    tail FILE_NAME NUMBER_OF_LINES_TO_TAIL
"""
import sys

def seek_eof(file):
    file.seek(0, 2)


def eof_value(file):
    current = file.tell()
    seek_eof(file)
    eof = file.tell()
    file.seek(current)
    return eof 


def current_char(file):
    return file.read(1)


def seek_to_nth_line_from_eof(file, n):
    seek_eof(file)
    newlines = 0
    i = 0
    eof = file.tell()
    while newlines < n:
        if current_char(file) == b'\n':
            newlines += 1
        i -= 1
        file.seek(i - 1, 2)
    file.seek(i + 1, 2)


def tail(file_name, n):
    with open(file_name, 'rb') as file:
        seek_to_nth_line_from_eof(file, n)
        tailed = file.read(eof_value(file) - file.tell())
        print(tailed.decode('utf-8').strip())


tail(sys.argv[1], int(sys.argv[2]))