I'm trying to use gnuplot on my MacBook Air (Mac OS X 10.11.3). I have installed XQuartz by using homebrew after I installed gnuplot (with this YouTube video: https://www.youtube.com/watch?v=AR-GUSkqMCU). But gnuplot did not work and terminal showed: Terminal type is now 'unknown'.
For example, I wanted to plot sin(x) and I got a error message as the following:
gnuplot> plot(sin(x))
WARNING: Plotting with an 'unknown' terminal.
No output will be generated. Please select a terminal with 'set terminal'.