First, make sure that you have a "rooted" Android cell phone so you can do things like run Terminal and execute the su command to obtain root privileges.

Notice that in the above command I had to replace the truecolour option to the terminal type png, which overrides the default colors gnuplot uses.

In a terminal (the command line window found in the Accessories menu), using either of the two commands below show you who else is logged in and how long they've been idle.