Comment 2 for bug 94949

There's a workaround described at [1]: Install 'rlwrap' and run gnuplot as
  rlwrap -a -c -b\"\\\"\\\"\\\'\\\'\" gnuplot
You can add
  alias gnuplot="rlwrap -a -c -b\"\\\"\\\"\\\'\\\'\" gnuplot"
to your ~/.bashrc to do that automatically.

1 https://math65740.blogspot.com/2012/09/installing-and-running-gnuplot-on-ubuntu.html