The ArangoDB database server has two modes of operation: As a server, where it will answer to client requests and as an emergency console, in which you can access the database directly. The latter - as the name suggests - should only be used in case of an emergency, for example, a corrupted collection. Using the emergency console allows you to issue all commands normally available in actions and transactions. When starting the server in emergency console mode, the server cannot handle any client requests.
You should never start more than one server using the same database directory, independent of the mode of operation. Normally, ArangoDB will prevent you from doing this by placing a lockfile in the database directory and not allowing a second ArangoDB instance to use the same database directory if a lockfile is already present.
In Case Of Disaster
The following command starts an emergency console.
Note: Never start the emergency console for a database which also has a server attached to it. In general, the ArangoDB shell is what you want.
> ./arangod --console --log error /tmp/vocbase ArangoDB shell [V8 version 126.96.36.199, DB version 3.x.x] arango> 1 + 2; 3 arango> var db = require("@arangodb").db; db.geo.count(); 703
However, it is very likely that you will never need the emergency console unless you are an ArangoDB developer.