$ sudo apt-get install gnuplot

-> when $ sudo apt-get install gnuplot-x11
-> No wxt terminal
-> $sudo apt-get install gnuplot

Q: Want to have default terminal wxt
When > terminal type set to ‘unknown’

at home directory

make file,

.gnuplot

add line

set term wxt

done

you will see the

    G N U P L O T
    Version 5.0 patchlevel 3    last modified 2016-02-21 

    Copyright (C) 1986-1993, 1998, 2004, 2007-2016
    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 set to 'wxt'