[R] Environmental variables

Gad Abraham
Mon, 02 Feb 2009 04:45:33 -0000

David Epstein wrote:
> I use a Mac (10.4.11 Mac Os X).
>
> In my .tcshrc I define an environmental variable MY.
> Is it possible to find out its value from inside R? When one loads
> R for Mac OS X Cocoa GUI written by:
> 	Simon Urbanek
> 	Stefano M. Iacus
> are files like .tcshrc read by R?
>
> Can I make the value of this environmental variable available to R?
>
> Sys.getenv() produces a lot of output, with the values of many
environmental
> variables, but not this one.
>
> Do I need a file with the correct value of MY, and have both R and my Unix
> shell read the same file, or is there a better way to proceed? I want to
> avoid duplicating the information in source files, as this can lead to a
> setup that is very hard to maintain.

R launched from the dock will not inherit variables from .bashrc or
.tcshrc because it's not a child process of the shell.

You have to set the variables in an XML file called environment.plist,
inside a directory .MacOSX in your home directory (create it if it
doesn't exist), e.g.:

macbook:~ gad$ cat .MacOSX/environment.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN"
"http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>PATH</key>

<string>/usr/bin:/bin:/usr/sbin:/sbin:/sw/bin:/usr/local/bin:/sw/sbin:/usr/X11/bin:/usr/local/git/bin</string>
	<key>JAVA_HOME</key>
	<string>/Library/Java/Home</string>
</dict>
</plist>



--
Gad Abraham
Dept. CSSE and NICTA
The University of Melbourne
Parkville 3010, Victoria, Australia
email: gabraham at csse.unimelb.edu.au
web: http://www.csse.unimelb.edu.au/~gabraham