Here are some uselful linux commands to start the GUI (Graphical User Interface) Windows from the shell terminal command:

For UNIX:
Code/Command:

xinit &



for Linux:
Code/Command:

startx



for Gnome:
Code/Command:

gnome&



for KDE:
Code/Command:

kde&



This command tell the X window system to run the Komon Desktop Environment (KDE):
for Motif Window Manager
Code/Command:

mwm &


for Blackbox
Code/Command:

blackbox &