ED2KLinks file
From AMule Project FAQ
The ED2KLinks file is an interface to communicate with aMule. Inspite of the External Connections interface, this interface is mono-directional. and inspite of the Online Signature interface, this one is in-going.
It consists of a regular text file in aMule's directory (in *nix systems that is at ~/.aMule/) which contains the eD2k links aMule should download.
As soon as aMule detects that file, it reads it, starts downloading the links in it, and deletes the file.
It might be of your interest to read this part of the aMule FAQ