[R] Calling R from a non-X shell script to plot?

[Liaw, Andy]

See
http://cran.us.r-project.org/doc/FAQ/R-FAQ.html#How-do-I-produce-PNG-graphic
s-in-batch-mode_003f

Andy

> From: doktora v
> 
> I am trying to run R from an apache C++ module in a shell script to
> plot some data to display it in apache later. I get the error
> (reported in apache's logs):
> 
> Xlib: connection to ":0.0" refused by server
> Xlib: No protocol specified
> Error in X11(paste("png::", filename, sep = ""), width, 
> height, pointsize,  :
>   unable to start device PNG
> In addition: Warning message:
> unable to open connection to X11 display`'
> Execution halted
> 
> Is anyone familiar with this (i.e. running R from a non-X
> environment)? Is there  a way to get around this? I've seen some stuff
> about virtual devices,  but have no idea if it works or where to
> start. If there is a simpler solution, please let me know.
> 
> -- doktora
> 
> 
> I run the following shell script from the apache module using execve:
> ------------------------------------------------------
> DISPLAY=:0.0
> export DISPLAY
> 
> if $R --vanilla --quiet < $rfile >$log ; then
>   echo "Success"
> else
>   echo "There were errors in $0, see $log"
> fi
> ------------------------------------------------------
> 
> And $rfile contains this:
> ------------------------------------------------------
> png(filename = "/tmp/plot.png", width = 510, height = 360);
> plot(<some graph>)
> dev.off()
> 
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