[R] Installing different R versions

[Martin Maechler]

>>>>> Loris Bennett <loris.bennett at fu-berlin.de>
>>>>>     on Thu, 8 Oct 2015 12:07:20 +0200 writes:

    > Dear Luca, Luca Cerone <luca.cerone at gmail.com> writes:

    >> Dear Loris and Wolfgang, thanks a lot for the help!
    >> 
    >> I wasn't aware of the module project. I'd rather use the
    >> "official" way of having co-existent R versions in this
    >> case, but is a good tool to know!

    > As far as I can tell from a quick look, "R Installation
    > and Administration", as referred to by Wolfgang, just
    > tells you how to install different versions in different
    > places by using the configuration option --prefix (for
    > Linux at least).  This is some thing you always have to
    > do, if you want to install several versions in parallel.

    > However, once you have multiple versions installed, you
    > need a mechanism to allow users to choose between them.
    > This is where Environment Modules come in.  At the
    > simplest level, they just allow environment variables to
    > be set and unset in an easy and consistent way.

    > So it is not a question of "using the 'official' way of
    > having co-existent R versions", but rather of installing
    > various versions and then enabling people to choose easily
    > between them.

    > Or have I missed some intrinsic feature of R which will
    > allow me to switch between installed versions without
    > having to explicitly tweak environment variables?

Yes, you have missed something.
I have installed many dozen versions of R simultaneously both at
work and on my laptop ... all under Linux.
(Yes, I am extreme - as R Core member wanting to be able to go
 back and see ...)

I don't need any environment variables, but just symbolic links
to define 'R', 'R-devel', 'R-patched', 'R-3.2.2', etc etc. in
our default PATH.
So these work from the shell (or similar), and 
even ESS (Emacs Speaks Statistics) is automagically picking up
all these, so I can use
   M-x R
   M-x R-3.2.2
   M-x R-devel
   etc
   
to have different versions of R running simultaneously "inside" ESS.

Martin

    > Cheers,

    > Loris

    > -- 
    > This signature is currently under construction.
(let's you'll converge ;-)