FUsage prints configuration help into the custom output.

GetDescription returns a description of environment variables.

ReadConfig reads configuration file and parses it depending on tags in structure provided.

ReadEnv reads environment variables into the structure.

UpdateEnv rereads (updates) environment variables in the structure.

Usage returns a configuration usage help.

DefaultSeparator is a default list and map separator character.

TagEnv - name of the environment variable or a list of names.

TagEnvDefault - default value.

TagEnvDescription - environment variable description.

TagEnvLayout -value parsing layout (for types like time.Time).

TagEnvPrefix - flag to specify prefix for structure fields.

TagEnvRequired - flag to mark a field as required.

TagEnvSeparator - custom list and map separator.

TagEnvUpd - flag to mark a field as updatable.

Setter is an interface for a custom value setter.

Updater gives an ability to implement custom update function for a field or a whole structure.