set style { data | function } {<style option>}
The set style data command affects the default style with which data from files is plotted. Likewise the set style function command changes the default style with which functions are plotted. Any valid style modifier which can follow the keyword with in the plot command can be used. For example, the commands
set style data points set style function lines linestyle 1
would cause datafiles to be plotted, by default, using points and functions using lines with the first defined line style.