Many plotting styles are available in gnuplot. They are listed alphabetically below. The commands set style data and set style function change the default plotting style for subsequent plot and splot commands.
plot 'data' with boxes, sin(x) with lines
Each plot style has its own expected set of data entries in a data file. For example, by default the lines style expects either a single column of y values (with implicit x ordering) or a pair of columns with x in the first and y in the second. For more information on how to fine-tune how columns in a file are interpreted as plot data, see using.