Today the Port of the week is x11/arandr, it’s a very simple tool to set-up your screen display when using multiple monitors. It’s very handy when you want to make something complicated or don’t want to use xrandr in command line. There is not much to say because it’s very easy to use!
It can generates your current configuration as a script that you will find
~/.screenlayout/ repertory. This is quite useful to configure your
screens from your ~/.xsession file in case a monitor is connected.
xrandr | grep "HDMI-2 connected" && .screenlayout/dual-monitor.sh
If HDMI–2 has a screen connected, when I log-in my session, I will have my dual-monitor setup!