You can use xdotool for automation. Install on Ubuntu with
sudo aptitude install xdotool
Then you can search for windows and send keys or mouse events, see man xdotool
for the full documentation. I use following script on Ubuntu 16.04 LTS during development:
WID=`xdotool search --name "Mozilla Firefox" | head -1`
xdotool windowactivate $WID
xdotool key F5
Note: in the older versions, e.g. Ubuntu 14.04 the flag is --title
instead of --name
.
See also the xdotool project site.