The oplot output is POSTSCRIPT, but in combination with the incredible ghostscript program, you can convert your plots to other device formats. For example, to generate a GIF picture from your output file, you can do the following:
% oplot < input.plt > tmp.ps % gs -sDEVICE=gif8 -sOutputFile=junk.gif tmp.ps
The GIF file can be then viewed using xv, for example. GIF is a standard image format, and you display it on the Mac if you have a public domain program called Giffer. This will also enable you to create a PICT file, which you can import into a word-processing or drawing program.
Ghostscript is also extremely convenient for getting previews of your plots:
% oplot -gz < plot.plt | gs -
and will save enormous amounts of paper.