The EAGLE Layout Editor is an easy to use, yet powerful tool for designing printed circuit boards (PCBs). The name EAGLE is an acronym, which stands for Easily Applicable Graphical Layout Editor. The program consists of three main modules (Layout Editor, Schematic Editor, and Autorouter) which are embedded in a single user interface. If EAGLE prompts for a license key the first time it is run, point it toward the freeware license file located at /opt/eagle-VERSION/bin/freeware.key, or purchase a license to unlock advanced features. After the key is accepted, you may wish to change the permission of /opt/eagle-VERSION/bin/eagle.key so that it is no longer world-writable. chmod 0644 /opt/eagle-VERSION/bin/eagle.key