linux ulimit with java does not work properly

Question

I run code on linux ubuntu 17.10

public class TestExec {
public static void main(String[] args) {
    try {
        Process p = Runtime.getRuntime().exec(new Str         


        

Answer 1

You get the same result if you run the same command from the command line:

$ "/bin/sh" "-c" "ulimit" "-n"
unlimited

This is because -c only looks at the argument immediately following it, which is ulimit. The -n is not part of this argument, and is instead instead assigned as a positional parameter ($0).

To run ulimit -n, the -n needs to be part of that argument:

$ "/bin/sh" "-c" "ulimit -n"
1024

In other words, you should be using:

new String[]{"/bin/sh", "-c", "ulimit -n"}