# Directories

StreamLink and Liberator can use a directory based hierarchical name space for data items such as records. Directories can be used as a means of organising information into groups and hierarchies.

For example, all Foreign Exchange instruments may be grouped under the directory `/FX`

where

* "/" is the root directory
* "FX" (Foreign Exchange) is a directory underneath the root

All the FX instruments would be grouped underneath `/FX`, and the subject that identifies an instrument includes the directory path.

The "/" delimiter is used to segregate levels of the directory hierarchy

For example, the FX instrument with symbol `EURUSD` (Euros to US Dollars) has the subject:

```
/FX/EURUSD
```

A client can [subscribe](datasource-subscriptions.md) to a directory, and StreamLink then informs the client when items are created or deleted within that directory. When you subscribe to a directory you don’t get an automatic subscription to the items in the directory; you have to explicitly subscribe to them as required.

**📌 NOTE**\
If you want your client application to automatically subscribe to the items in a list, use a [container](datasource-containers.md) subscription rather than a directory subscription.