How to run parallel for loops

Question

I am not very familiar with bash, but would like to break this code so that I can run it on a server with 12 processors:

#!/bin/bash #bashScript.sh for i in {1..209} do Rscript Compute.R $i done 

How can I achieve this?

Thanks!

Answer 1

Use xargs with the --max-procs ( -P ) option. If there are enough arguments, xargs will use exactly this number of parallel processes to process input:

 #! /bin/bash seq 209 | xargs -P12 -r -n1 Rscript Compute.R 

Answer 2

Try:

 #!/bin/bash #bashScript.sh for i in {1..209} do Rscript Compute.R $i & done 

Answer 3

Using the GNU Parallel Interface:

 parallel Rscript Compute.R ::: {1..209} 

Installation in 10 seconds:

 wget -O - pi.dk/3 | sh 

Watch the video for a quick introduction: https://www.youtube.com/playlist?list=PL284C9FF2488BC6D1