variables help / update config file

[Gribouillis]

Besides Buran's suggestion to use configparser, your program can have a strategy such as:

• If the program is called with -c or --config option, use the config file given on the command line
  
• Otherwise use myprog.cfg file from the current directory
  
• Otherwise use a user default config file such as ~/.config/myprog/default.cfg
  
• Otherwise use a system-wide default config file ...
  

There are many options for this.