import os
import time

source = ['C:\\py\\', 'C:\\work\\']
target_dir = 'C:\\backup'
today = target_dir + os.sep + time.strftime('%Y%m%d')
now = time.strftime('%H%M%S')

if not os.path.exists(today):
    os.mkdir(today)
    print('Successfully create directory', today)

target = today + os.sep + now + '.rar'

zip_command = 'C:\\"Program Files"\\WinRAR\\rar a {0} {1}'.format(target, ' '.join(source))
print(zip_command)

if  os.system(zip_command) == 0:
    print('Successful backup.', target)
else:
    print('Backup FAILED.')