Running a shell script from java code [duplicate]

Answer 1

Your code is right and I am sure you are not getting exceptions, if you read using proc.getErrorStream() you will not get anything.
Commands 100% get executed that way, having said that now thing is that you are echo'ing something and you need to read it back using BufferedReader.

Check below example which will successfully create a directory called "stackOverflow" and print what you are echo'ing. For the putting it into a log file I am afraid that you can do it using ">", you may have to use some editor command or create file using Java.

Bottom line: Runtime.getRuntime().exec("command") is the correct and defined way to execute Unix commands or scripts from Java and it WORKS.

test.sh

#!/bin/bash
echo "hola"
mkdir stackOverflow

Test.java

import java.io.*;
public class Test {

        public static void main(String[] args) throws Exception {
                try {
                        String target = new String("/home/hagrawal/test.sh");
// String target = new String("mkdir stackOver");
                        Runtime rt = Runtime.getRuntime();
                        Process proc = rt.exec(target);
                        proc.waitFor();
                        StringBuffer output = new StringBuffer();
                        BufferedReader reader = new BufferedReader(new InputStreamReader(proc.getInputStream()));
                        String line = "";                       
                        while ((line = reader.readLine())!= null) {
                                output.append(line + "\n");
                        }
                        System.out.println("### " + output);
                } catch (Throwable t) {
                        t.printStackTrace();
                }
        }
}