txt_unwrap_lines.py

#!/usr/bin/python3.5
# -*- coding: utf-8 -*-

# keywords: unwrap lines, OCR, pdftotext

import sys
import os
import re

def txt_unwrap_lines():

    conversions = [
    	# trim space and \12 to just space
        ['( )(?=[a-zżźćńółęąś„\(\[])', ' '],
        # delete new line characters if next row starts from small letter
        ['(\n){1,2}(?=[a-zżźćńółęąś„\(\[])', ' '],
        # delete - from '-.' case
        ['(-)(?=\.)', '']
    ]

    if len(sys.argv) < 3:
        raise ValueError("Example: txt_unwrap_lines input.txt output.txt")

    input_filename = sys.argv[1]

    if not os.path.isfile(input_filename):
        raise ValueError("Input file does not exist.")

    with open(input_filename, 'r') as f:
        changed = f.read()

    for c in conversions:
    	changed = re.sub(c[0], c[1], changed)

    with open(sys.argv[2], 'w') as f:
        f.write(changed)

if __name__ == "__main__":
    txt_unwrap_lines()