[Rd] Rscript -e does not accept newlines under Linux?

Dirk Eddelbuettel edd @ending from debi@n@org
Mon Sep 17 13:37:46 CEST 2018

On 17 September 2018 at 07:09, Duncan Murdoch wrote:
| I would not assume that shell behaviour in Windows and Unix would always 
| be the same.  A better comparison would be to list some other command on 
| the same system that behaves differently.  For example, on MacOS I see
| $ echo 'ls()
|  > ls()'
| ls()
| ls()
| which suggests that what you wrote should be legal, but the form of that 
| command is different: there's no equivalent of "-e".  Maybe someone else 
| who knows Unix shell behaviour better can comment on whether they'd 
| expect your Rscript command to work.

When we wrote littler, ie 'r', just before Rscript was added to R itself, the
ability to work from standard input just like any other Unix tool does was in
fact a design feature.  So with littler it works (and you need -p to print as
we are silent by default by another design choice)

  edd using rob:~$ (echo "ls()"; echo "ls()")
  edd using rob:~$ (echo "ls()"; echo "ls()") | r -p
  [1] "argv"
  [1] "argv"
  edd using rob:~$

argv is a global variable to hold the arguments (as in C).

Hence standard things work the way you expect them to:

  edd using rob:~$ echo "set.seed(123); print(summary(rnorm(1e6)))" | r 
      Min.  1st Qu.   Median     Mean  3rd Qu.     Max. 
  -4.79919 -0.67439 -0.00026 -0.00052  0.67333  4.85077 
  edd using rob:~$ 

just like r -e ... would, or R -e do now.  It is harder to do this for R and
Rscript due to the way they are invoked, setting shell variables and all that
before calling into $R_HOME/exec/bin/R.


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

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