The config system is used for user-configurable options. They are backed by environment variables and config files.
Here are the layers of config, with each layer overriding the layer below it:
| Config hierarchy |
|---|
| Command line argument |
| Environment variable |
| Config file |
Use the config_dir and config_env_var_prefix options in the constructor of CLI to set the config directory and environment variable prefix.
Here's an example:
Let's assume config_dir=~/.myconfig and config_env_var_prefix='CLI'.
Environment variable format export PREFIX_SECTION_OPTION=value.
Config file format:
[section]
option = value
So to set the output type of commands, a user can set the environment variable CLI_CORE_OUTPUT or specify the section and option in the config file.
The environment variable will override the config file.
Lastly, some configurations (like output type) can be specified on a command-by-command basis also.