NAME

       md_doc_help_elektra-cascadingelektra-cascading(7) -- of key names
        - Cascading is the triggering of secondary actions. For configuration it means that first
       the user configuration is read and if this attempt fails, the system configuration is used
       as fallback.

       The idea is that the application installs a configuration storage with default settings
       that can only be changed by the administrator. But every user has the possibility to
       override parts of this system configuration regarding the user's needs in the *user
       configuration. To sum up, besides system configuration, users have their own key databases
       that can override the settings according to their preferences.

       Thus when a key starts with / such cascading will automatically performed.

       Keys in spec allow us to specify which keys are read by the application, which fallback it
       might have and which is the default value using meta data. The implementation of these
       features happened in ksLookup. When cascading keys (those starting with /) are used
       following features are available (in the meta data of respective spec-keys):

       • override/#: use these keys in favour of the key itself (note that # is the syntax for
         arrays, e.g. #0 for the first element, #_10 for the 11th and so on)

       • namespace/#: instead of using all namespaces in the predefined order, one can specify
         which namespaces should be searched in which order

       • fallback/#: when no key was found in any of the (specified) namespaces the fallback-keys
         will be searched

       • default: this value will be used if nothing else was found

   CASCADING
       When cascading keys (those starting with /) the lookup will work in the following way (it
       can be debugged with kdb get -v):

       1.) In the spec-key the override/# keys will be considered. 2.) If, in the spec-key, a
       namespace/# exist, those namespaces will be used. 3.) Otherwise, all namespaces will be
       considered, see here. 4.) In the spec-key the fallback/# keys will be considered. 5.) In
       the spec-key the default value will be returned.

       See application integration for how to use cascading names in the context of applications.

       Read more about namespaces.