I'm using ubuntu 20.04 LTS in windows 10

   G N U P L O T
    Version 5.2 patchlevel 8    last modified 2019-12-01

    Copyright (C) 1986-1993, 1998, 2004, 2007-2019
    Thomas Williams, Colin Kelley and many others

    gnuplot home:     http://www.gnuplot.info
    faq, bugs, etc:   type "help FAQ"
    immediate help:   type "help"  (plot window: hit 'h')


Terminal type is now 'wxt'
gnuplot> plot sin(x)
Unable to init server: Could not connect: Connection refused
19:59:45: Error: Unable to initialize GTK+, is DISPLAY set properly?
Failed to initialize wxWidgets.

Terminal type is now 'unknown'
     wxt init failure
gnuplot>