Unable to init server: Could not connect: Connection refused (gedit:207): Gtk-WARNING **: 16:33:17.226: cannot open display: code example

Example: Unable to init server: Could not connect: Connection refused (gedit:7575): Gtk-WARNING **: 10:17:11.806: cannot open display:

Unable to init server: Could not connect: Connection refused

(gedit:7575): Gtk-WARNING **: 10:17:11.806: cannot open display: