[R] A couple of batch mode questions

[MacQueen, Don]

From my perspective, which is a unix-alike perspective, Rscript makes R useable in exactly the same way as other unix style scripting languages such as perl,  tcsh, bash, etc. This is useful, and a good thing. If I remember (and understood) correctly, it is why Rscript was introduced, later in R's history than BATCH.

Scripts run using Rscript can be (slightly) more self-contained, which I suppose might or might not be an advantage, depending on one's needs:

To run an R script using Rscript, I type
   ./myRscript.r
at the command line (less typing), whereas with batch mode, it has to be
   R CMD BATCH myRscript.r
(more typing) but if I want any R options applied, such as --no-restore or --no-save, I include them within the script when using Rscript, but have to put them on the command line outside the script when using BATCH.

One can actually execute an R command at the shell prompt using Rscript, which can't be done with BATCH:

[296]% Rscript -e 3+4
[1] 7
[298]% Rscript -e 'sqrt(2)'
[1] 1.414214

If I want to pass custom parameters to the script (script-specific parameters of my own that I put on the command line), the syntax for either supplying them or parsing them might be different. I'm not sure, since I don't do this very often, and never use CMD BATCH. But it would be worth checking.

-Don

--
Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
Lab cell 925-724-7509
 
 

On 7/25/18, 8:22 AM, "R-help on behalf of Rich Shepard" <r-help-bounces using r-project.org on behalf of rshepard using appl-ecosys.com> wrote:

    On Wed, 25 Jul 2018, Bert Gunter wrote:
    
    > "Within R one can use source() to run a batch file of R commands, while R
    > CMD BATCH and Rscript are run from the command line. Is this correct?"
    >
    > Yes.
    
    Bert,
    
       Thanks for confirming.
    
    > I think your query answers your query: You use Rscript when you want to use
    > R in the command environment, perhaps as part of an analytical pipeline;
    > and you source an R file when you want to work within R.
    
       That's a given. Why would I prefer Rscript over R CMD BATCH, or
    vice-versa? I did not see much difference between the two in their help
    files.
    
    Regards,
    
    Rich
    
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