See Features
ELS uses a publisher/subscriber paradigm to present a collection of logical libraries from a local workstation or publisher to a subscriber, or back-up. The subscriber may be local, with all storage devices attached, or remote using another ELS instance operating as a Subscriber Listener.
Each logical library may span multiple storage devices. This is the same approach used by modern media streaming systems, such as Plex or Jellyfin, but is also useful for anyone producing large volumes of content, videos, music, images, data, etc. Each storage Location may specify a "Minimum Free Space". A library is defined as a Bibliography of Sources used by the library.
ELS may be run in a variety of modes. The visible mode is this ELS Navigator. However, several other command line modes are available to automate ELS operations. ELS started as a command line back-up tool. The addition of the Navigator desktop application in Version 4 added significant functionality.
The Browser presents a publisher/workstation and subscriber in a drag 'n drop interface. Selections made in the Browser are used by the Tools and Jobs. Selections may be changed while working with Tools and Jobs, e.g. using the Duplicate Finder select the Publisher and click "Run ...", then select the Subscriber and click "Run ..." again.
The Publisher and Subscriber tabs present the logical library structure. The System tabs present that computer's entire directory tree.
Libraries are the core of ELS that define the parameters of an ELS instance. Those include how to access ELS remotely, which files to ignore, minimum storage space for each location, and the names and source(s) of each logical library.
If a Subscriber is remote or Hints will be used Hint Keys and Authentication Keys are required. Use the System menu to define those using the keys from the library files.
Hints are a mechanism to coordinate manual changes to a collection at back-up time. Hints allow changes (deletes, moves and renames) to be made when not all subscribers are actively connected. A publisher may be opened as a Collection, where Hints are tracked, or as a Workstation where Hints are not tracked. See Hints in the ELS Wiki for more information.
A Hint Tracker is local whereas a Hint Server is an ELS instance operating as a remote Hint Server listener.
Authentication Keys define ELS instances that are allowed to connect to this ELS when operating as a Subscriber Listener or Hint Server. Those may include publishers/workstations, subscribers and Navigators.
Hint Keys defined which publishers and subscribers are involved in Hint tracking.
Blacklist and Whitelist define which IP addresses are allowed to connect to ELS when operating as a Subscriber Listener or Hint Server. Optional but a good way to avoid hack attempts.
See Communications in the ELS Wiki for more information.
Various Tools are provided to make building and maintaining a collection easier. The Duplicate Finder and Empty Directory Finder are used manually. The other Tools may be run by themselves or combined into Jobs.
And some Tools are built-in and will be used if configured. Those are:
Jobs are composed of one or more Tasks which are a Tool with selections for the Publisher, Subscriber, and Hint Server as required. Some Tools also use Origin path lists to define where to execute the Tool.
Tools define something to do. Tasks in Jobs define where to do it.
ELS is a multi-faceted application that may be executed in a variety of ways.
The provided start-up mechanism for each supported operating system executes the ELS Navigator user interface with no arguments. That tells Navigator to use the previous publisher, subscriber, etc.
Inside Navigator there are two execution tools:
ELS may also be executed from the command line two ways. See Command Line in the ELS Wiki for details.
When executing ELS from the command line with cron, or a task scheduler, set the -c | --console-level option to Off so it only logs to the -d | --debug-level file and not stdout to avoid cron error messages.