echo 'js document.documentElement.outerHTML' | socat - unix-connect:$5

* But this returns the source contaminated with various other messages e.g. EVENT notifications like keypresses! –Chris2048

Good for overall multi-instance-management from within a shell script.

You can echo any valid uzbl command into the socket(s) this way.

for socket in /tmp/uzbl_socket_*; do
  echo 'print @uri' | socat - unix-connect:$socket
done