My one main display is cracked

All i have is termial i can open and no other things. Is there any way to set external display as default by terminal.
How i open display setting on my external display to set it as default display…
Please help me with this…

open a terminal
then do xrandr
This will output the available screen ports, e.g. LVDS-1 is the laptop screen and VGA-1 is the port for external monitor (could be also HDMI-1, …). You can mirror the screen with command xrandr --output VGA-1 --same-as LVDS-1 . This will mirror between Laptop screen and VGA output. Names and outputs are depending on your system.

Thank you so much

no problem