Basic information about the Eagle PCB backend and sch2eaglepos.sh

gnet-eagle.scm  

The script uses the component's package, footprint, value, and (if no
value) device attributes, as well as the netlist, to generate an Eagle
script that will add and connect all components.  It also introduces a
"lib" attribute, which specifies the Eagle library where the footprint
can be found...if a "lib" attribute is not set for a component, then
the library defaults to "smd-ipc" (the default Eagle surface mount library).

sch2eaglepos.sh

I am also including a simple shell script that I wrote which has saved
me hours by extracting the relative locations of the parts from a
gschem schematic, and generating an Eagle script to place the
components in the same relative locations on the layout.  By default
all packages are piled on top of each other, and with a large design
it takes a long time to sort out which cap bypasses which IC, etc.