Changing font for Cinnamon and Gnome shells.

patchthemes.py

#!/bin/env python3
# -*- coding: utf-8 -*-
import os
import sys
import argparse

THEME_PATH = '/usr/share/themes'
HOME_THEME_PATH = os.path.join(os.environ['HOME'],'.themes')

# [0] theme path, [1] theme name, [2] shell name, [3] font list
TEMPLATE = '@import url("file://{0}/{1}/{2}/{2}.css");\nstage {{ font-family: {3}; }}'

"""
Usage: ./patchthemes.py YourFontName1 YourFontName2

You can run it without args to use only sans-serif font.
--serif or -s will use serif font as fallback.
--force or -f will replace files in home path if they exist.
"""
def main(args):

	try:
		lang, country = os.environ['LANG'].split('.')[0].split('_')
		if lang in ('ru','be','uk') or country in ('RU','BY','UA'):
			phrases = {
				'desc': 'Патч шрифта для панелей Cinnamon и Gnome.',
				'fonts_meta': 'ШРИФТ',
				'fonts_desc': 'имя шрифта для использования',
				'serif_desc': 'использовать шрифт с засечками как fallback (по умолчанию без засечек)',
				'force_desc': 'заменять существующие файлы',
				'exist_error': 'Файл {} существует (используйте --force для замены)',
				'nowrite_error': 'Не удалось записать изменения в {}, возможно, файл открыт в другом приложении, или у пользователя нет прав для его изменения.'
			}
		else:
			raise Exception

	except:
		phrases = {
			'desc': 'Patch Cinnamon and Gnome shell theme font.',
			'fonts_meta': 'FONT',
			'fonts_desc': 'font name to use',
			'serif_desc': 'use serif font for fallback instead of sans-serif',
			'force_desc': 'replace existing files',
			'exist_error': 'File {} exists (use --force to replace)',
			'nowrite_error': 'Can\'t write changes to {}, maybe file is used by other program or this user have no rights to edit it.'
		}
	

	parser = argparse.ArgumentParser(description=phrases['desc'])
	parser.add_argument('fonts', metavar=phrases['fonts_meta'], nargs='*', help=phrases['fonts_desc'])
	parser.add_argument('--serif', '-s', action='store_true', help=phrases['serif_desc'], default=False)
	parser.add_argument('--force', '-f', action='store_true', help=phrases['force_desc'], default=False)
	parsed_args = parser.parse_args(args)

	font_list = []
	
	for f in parsed_args.fonts:
		font_list.append('"{}"'.format(f) if ' ' in f else f)

	font_list.append('serif' if parsed_args.serif else 'sans-serif')
	fonts = ", ".join(font_list)

	with os.scandir(THEME_PATH) as it:
		for entry in it:
			if not entry.is_dir():
				continue

			for sh in ('cinnamon', 'gnome-shell'):

				filepath = "{0}{1}{0}.css".format(sh, os.path.sep)

				if not os.path.exists(os.path.join(entry.path, filepath)):
					continue

				home_file_path = os.path.join(HOME_THEME_PATH, entry.name, filepath)

				if os.path.exists(home_file_path) and not parsed_args.force:
					print(phrases['exist_error'].format(home_file_path))
				else:
					try:
						os.makedirs(os.path.join(HOME_THEME_PATH, entry.name, sh), mode=0o755, exist_ok=True)
					except:
						pass
					
					try:
						with open(home_file_path, mode='w', encoding="utf-8") as f:
							f.write(TEMPLATE.format(THEME_PATH, entry.name, sh, fonts))
					except:
						print(phrases['nowrite_error'].format(home_file_path))
					

if __name__ == '__main__':
	main(sys.argv[1:])