[R] how to add error bar to the data in R?

[Gabor Grothendieck]

 <jz7 <at> duke.edu> writes:

: Does anyone knwo how to add error bar to the data point in a simple
: xyplot? Right now, I have a .dat file including both the data points and
: their standard deviation and read it in R. I tried function arrows(). But
: it didn't gave me any arrows.

See errbar in package Hmisc and plotCI in package gregmisc.