input_file = open('file.txt', 'r')
for line in input_file:
    print line

from itertools import islice
with open('file.txt') as fin:
    lines = islice(fin, 1000000, 2000000) # or whatever ranges
    for line in lines:
        # do something

import linecache

for i in xrange(1000000, 2000000)
    print linecache.getline('file.txt', i)

input_file = open('file.txt', 'r')
for index, line in enumerate(input_file):
    # Assuming you start counting from zero
    if 1000000 <= index <= 2000000:
        print line

4.373  4.418  4.395    tail -n+50000000 test.in | head -n10
 5.210  5.179  6.181    sed -n '50000000,50000010p;57890010q' test.in
 5.525  5.475  5.488    head -n50000010 test.in | tail -n10
 8.497  8.352  8.438    sed -n '50000000,50000010p' test.in
22.826 23.154 23.195    tail -n50000001 test.in | head -n10
25.694 25.908 27.638    ed -s test.in <<<"50000000,50000010p"
31.348 28.140 30.574    awk 'NR<57890000{next}1;NR==57890010{exit}' test.in
51.359 50.919 51.127    awk 'NR >= 57890000 && NR <= 57890010' test.in

lines_data = []
text_arr = multilinetext.split('n')
for i in range(line_number_begin, line_number_end):
    lines_data.append(multilinetext[i])