split.py

#!/usr/bin/python
import sys


def breakdown(filename, chunk):
    lines = []
    line_counter = 0
    file_counter = 0

    with open(filename) as file:
        for line in file:
            line_counter += 1
            lines.append(line)
            if line_counter == int(chunk):
                file_counter += 1
                writeSmall(lines, line_counter, file_counter)
                lines = []
                line_counter = 0

    if line_counter:
        writeSmall(lines, line_counter, file_counter)


def writeSmall(lines, line_counter, file_counter):
    with open('file_{0}_part{1}.txt'.format(line_counter, file_counter), 'w') as smallfile:
        print("writing {0} lines to file_{1}_part_{2}.txt".format(
            line_counter, line_counter, file_counter))
        smallfile.write(''.join(lines))


if __name__ == "__main__":
    if len(sys.argv) > 1 and sys.argv[1] is not None or sys.argv[2] is not None:
        filename = sys.argv[1]
        chunk = sys.argv[2]

        breakdown(filename, chunk)
    else:
        print("Please enter filename and chunk size")

Running the program:

1. chmod +x split.py

2. ./split.py <file_name> <chunk_size>
   eg. ./split.py book.txt 2000