The Suns have the capability of displaying the typeset (.dvi)
version of the file, without having to print it on paper.
This is called previewing. This is good for making
corrections in your early versions where you have lots of
big mistakes.
Please! Don't print up your stuff after every correction! Laser printing is expensive! Use the previewer initially for cleaning up drastic errors. Print only the last draft or two for fine tuning.
The standard previewer is xdvi. You invoke it by typing, for example,
xdvi mythesis
mythesis.dvi. The first page of the
paper will appear.
Click on the boxes on the right-hand side of the window to move around in the file or change the magnification. You can also use the mouse directly on your document to magnify one portion of it--the different buttons produce magnified rectangles of different sizes.
The keyboard commands are summarized in the manual page for
xdvi, which you can read by typing man
xdvi. Briefly, p moves you back, space moves you
forward, and q quits. You can also type a
number followed by space or p to go forward or back
several pages at once. One especially useful key is capital
R, which forces the .dvi file to be reread.
So you can change your document in one window,
run 
in another to format it , and then go to the xdvi window
and type capital R to see the changes.