[Rd] The Environment variables settings in bin/R, why do they ignore environment variables of the same name?

[Dirk Eddelbuettel]

On 26 February 2015 at 16:20, Saptarshi Guha wrote:
| In installation/R/bin/R i notice
| 
| 1. R_HOME_DIR is hard coded e.g.
| R_HOME_DIR=/usr/local/lib64/R
| 
| 2. It ignores R_HOME_DIR
| 
| echo "WARNING: ignoring environment value of R_HOME"
| 
| 3. R_SHARE_DIR, R_INCLUDE_DIR and R_DOC_DIR are also hard coded.
| 
| Is there a reason why these  settings do not read the values from the
| environment variables of the same name (assuming they exist) and
| defaulting to these hard coded values in case they dont?

AFAICR you supposed to deal with this via $PATH and just pick one:

Ie with

  edd at max:~$ grep ^R_HOME_DIR /usr/lib/R/bin/R /usr/local/lib/R-devel/bin/R                                                                                                                                            
  /usr/lib/R/bin/R:R_HOME_DIR=/usr/lib/R
  /usr/local/lib/R-devel/bin/R:R_HOME_DIR=/usr/local/lib/R-devel/lib/R
  edd at max:~$ 

I get, respectively,

  edd at max:~$ R --version | head -1
  R version 3.1.2 (2014-10-31) -- "Pumpkin Helmet"
  edd at max:~$ PATH="/usr/local/lib/R-devel/bin/:$PATH" R --version | head -1
  R Under development (unstable) (2015-02-22 r67876) -- "Unsuffered Consequences"
  edd at max:~$ 

and I have R-devel aliased to RD and R-devel in /usr/local/bin.

Dirk

-- 
http://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org