ggplot2 - Font size on R ggpolt2 barchart -

this code barchart:

ggplot(d, aes(x=column1, y =column2)) + geom_bar(position=position_dodge()) +           opts(panel.background = theme_rect(fill='white', colour='white')) 

column1 - names of bars.

how can make font of names bigger?

to change size of x axis labels should use axis.text.x= inside opts() (if use old version of ggplot2) or inside theme() (starting ggplot2 version 0.9.1).

+opts(axis.text.x=theme_text(size=13))  +theme(axis.text.x=element_text(size=13))