I know this is very noobish question but only way to get through this is ask for help.
So here it is, I installed octave-4.2.1 from octave-4.2.1.tar.xz by following standard procedure of extracting , ./configure, make , make install etc. It seems only octave-cli is installed when I fire octave–force-gui nothing happens. My question is what all I must do in order to get octave-gui working? also if it’s not installed how can I install it without hampering octave-cli?