Calling bash script from Java

Question

I have this MCVE for an Java class calling a bash script:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

class Test
{
        static BufferedReader in;
        public static void main(String[] args) throws Exception
        {
                String[] cmd = new String[]{"/bin/sh", "/usr/myapp/myscript.sh", "parameter1"};
                Process pr = Runtime.getRuntime().exec(cmd);
                in = new BufferedReader(new InputStreamReader(pr.getInputStream()));
                String line = in.readLine();
                while(line != null)
                {
                        System.out.println(line);
                        line = in.readLine();
                }

        }
}

When I have the compiled .class file in the same directory as myscript.sh, it works just fine. As soon as I move the .class file to another folder, it doesn't execute the script anymore, although I am still using the absolute path to the script.

I tested this with JDK 1.8 on a BeagleboneBlack running Angstrom if this information is good for something.

How can I run the script, although it is in a different location?

Can you change `getInputStream` to `getErrorStream` in the above code and run it again? Hopefully you'll get some useful output — Samuel, May 21 '17 at 21:07

score 1 · Answer 1 · answered May 21 '17 at 22:45

1

Using the getErrorStream hint by Samuel really helped.

It was clear, that some sub-scripts that were in the same folder as the original shell script were not found.

The solution was as easy as using absolute paths to sub-scripts as well since the working directory is not the one of the called script but the one of the calling application (in my case the Java App)

answered May 21 '17 at 22:45

mxcd

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Besides using absolute paths for sub-scripts, you could also try using the script *dir*, like this: `$(dirname "$0")/subscript`. – Paulo Mattos May 22 '17 at 03:17

Calling bash script from Java

1 Answers1