Split the file into separate files based on the line count.

split.py

import os
import sys

# defines the main function for the script
def main():
    # read the command line arguments for the file path.
    if(len(sys.argv) >= 2):
        file = sys.argv[1]
        lines = int(sys.argv[2])
        print 'Start: Split the %s file into files of %d lines'%(file, lines)

        count = split(file, lines)

        print 'Finished: Created %d files'%(count)

    else:
        print 'split.py file lines'

#   Split the file into separate files that contain the number of lines specified.
#   The last file will contain the remainder of the contents, when the number of lines is less
#   than requested.
def split(filepath, lines):

    path, filename = os.path.split(filepath)
    basename, ext = os.path.splitext(filename)
    count = 0

    # open input file
    f_in = open(filepath, 'r')

    try:

        # open the first output file
        f_out = open(os.path.join(path, '%s_%s%s'%(basename, 0, ext)), 'w')

        try:
            # loop over all lines in the input file, and number them
            for i, line in enumerate(f_in):
                # every time the current line number can be divided by the
                # wanted number of lines, close the output file and open a new one
                if i % lines == 0:
                    f_out.close()
                    f_out = open(os.path.join(path, '%s_%s%s'%(basename, i, ext)), 'w')
                    count += 1

                # write the line to the output file
                f_out.write(line)
        finally:
            # close the last output file
            f_out.close()

    finally:
        # close the input file
        f_in.close()

    return count

if __name__ == '__main__':
    main()