Return argument from R to bash

Question

I have the following bash script in which the R script is called

#!/bin/bash

declare -x a=33   
declare -x b=1       
declare -x c=0

Rscript --vanilla MWE.R $a $b $c

echo $a $b $c

I want to change bash variables in an R script and return their changed values ​​in a bash script, because then I pass the changed variables somewhere else. R script is

#!/usr/bin/env Rscript
args = commandArgs(trailingOnly=TRUE)

Rb = as.numeric(args[2])
Rc = as.numeric(args[3])

Rb = Rb + 1
Rc = Rc + 1

args[2]=Rb
args[3]=Rc

print(c(args[1],args[2],args[3]))

However, the conclusion printand, echoaccordingly:

[1] "33" "2"  "1" 
33 1 0

which shows that new values ​​are not passed from R to bash. What am I doing wrong?

Answer 1

Since it Rscriptdoes not allow manipulation of the environment variable, you will need to write the output Rfrom the program bash.

One of the many possibilities is to use array:

#!/bin/bash

declare a=33   
declare b=1       
declare c=0

declare -a RESULT
RESULT=($(Rscript --vanilla MWE.R $a $b $c))

a=${RESULT[1]}
b=${RESULT[2]}
c=${RESULT[3]}