If you need to recursively process an R function or an R script n times, you can extract the for loop in bash and process each R function or script with a different CPU. How to do it:

1. built a template R script
2. built a template bash script
3. use xargs bash fonction in a loop for processing each step of the loop with a different CPU

Save the R script below as ~/ost4sem/exercise/multicore/templateR.R

mod.t = Sys.getenv(c('mod','t','path'))
mod = as.numeric(mod.t[1])
t = as.numeric(mod.t[2])
path = as.character(mod.t[3])
 
print(mod)
print(t)
print(path)
 
my_output=paste("We have processed  mod ",mod," and t ",t," ---- output path is   ",path,sep=" ")
write.table(my_output,paste(path,"/my_mod",mod,"_t",t,".txt",sep=""))

Save the template bash script below as ~/ost4sem/exercise/multicore/templatebash.sh

#!/bin/bash
cd ~/ost4sem/exercise/multi_core
mod=$1
t=$2
path=~/ost4sem/exercise/multi_core/output
 
export mod
export t
export path
R --vanilla --no-readline  -q    <    template_R.R

cd ~/ost4sem/exercise/multi_core
for mod in 1 2 3 4 ; do 
for t in `seq 1 5` 
do echo $mod $t 
done 
done| xargs -n 2 -P 2 bash template_bash.sh