Your approaches are equivalent to calling ls with the specified arguments. In Bash notation, what you're running is:

ls ';' pwd
ls '&&' pwd

If you want ls and pwd to be run as separate commands, you can use Bash (or another shell language) to wrap them into a single command:

bash -c 'ls ; pwd'

which you can call this way:

ProcessBuilder processBuilder = new ProcessBuilder("bash", "-c", "ls ; pwd");

Why you don't create a method that take your command and return your result, like this you can execute many commands, and you can use it every where in your program, and if you need some changes you just change in this method and not in all your program:

Your code should be like so:

public static void main(String[] args) {
    String command1 = "echo hello";
    String command2 = "echo hi";
    System.out.println(executerCommand(command1));
    System.out.println(executerCommand(command2));
}

public static String executCommand(String command) {
    String line;
    String resultat = "";
    try {
        ProcessBuilder builder;

        builder = new ProcessBuilder("cmd.exe", "/c", command);

        builder.redirectErrorStream(true);
        Process p = builder.start();
        BufferedReader r = new BufferedReader(new InputStreamReader(p.getInputStream()));
        while (true) {
            line = r.readLine();
            if (line == null) {
                break;
            }
            resultat += line + "\n";
        }
    } catch (IOException e) {
        System.out.println("Exception = " + e.getMessage());
    }
    return resultat;
}

This return a result like this :

run:
hello

hi

BUILD SUCCESSFUL (total time: 0 seconds)

Hope this can help you

One problem is that your while loops

while ((buff = reader.readLine()) != null) { ... }

only terminate when the reader has reached the end of the input stream.

The end of the input stream is only reached when the subprocess terminates.

The second problem is that you seem to be using NodeJS as sample command executor.

• If NodeJS is started from a console, you can enter JavaScript statements and they are executed one by one.
• You are however starting NodeJS not from a console, but from some other application. In this case, NodeJS wants to read a complete script from stdin and executes the complete script at once
• You could start NodeJS with the -i parameter (force interactive mode), at the expense of some additional output.

To achieve this, you would create the ProcessBuilder with

ProcessBuilder pb = new ProcessBuilder("node", "-i");

Communicating with a subprocess in this way only works when you know how many lines to read from the reader before sending the next command.

Knowing how many lines to read can mean:

• knowing how many lines of output a command produces (login: 1 line of output, logout: no output)
• knowing that a command produces a distinct last line (for example an empty line or a line with only "END" in it)
• that a command produces a line count as the first result
• executing another command first that returns the result line count of the subsequent command

The list certs command could either:

• produce

    cert1 abc
    cert2 def
    END
  

• produce (where the last line would be empty instead of containing a dot)

    cert1 abc
    cert2 def
    .
  

• produce

    2 certs
    cert1 abc
    cert2 def
  

• or you could execute a count certs command before executing list certs

This is normal: two commands mean two processes. You need two ProcessBuilders, and check the return value of the first process before executing the second one.

This syntax:

new ProcessBuilder("javac","Mocha.java","&&","java","Mocha");

does not work. && is a logical shell operator, the javac command does not understand it. Do your processing logic in Java directly instead:

if (p1.waitFor() == 0) // compile succeeded
    // initiate second process

Best way to run command simultaneously is put all command in one scrip file an and then run that script file using Processbuilder

You can pass parameters as well.

$ cat myscript
#!/bin/bash
echo "First arg: $1"
echo "Second arg: $2"
$ ./myscript hello world
First arg: hello
Second arg: world

ProcessBuilder will only do one command at a time -- as you're discovering, when you pass it an array of Strings, only the first String is taken as a command, the rest are used as arguments.

To do more than one command, you'll need to create a new ProcessBuilder for each.

To make sure multiple commands run in sequence, you'll have to make sure one command finishes before you start the next, otherwise the order of execution will be uncertain.

The way you do this is to take the Process object returned by ProcessBuilder.start() and use its waitFor() method to wait for each command to complete.

I don't have a windows machine knocking about, but my guess would be to quote the && and msbuild as separate array entries.

{"cmd.exe",
"/c",
"C:\Program Files\Microsoft Visual Studio 10.0\Common7\Tools\..\..\VC\vcvarsall.bat",
"&&",
"msbuild"}

You don't need to include spaces. The ProcessBuilder will deal with that for you. Just pass in your arguments one by one, without space:

ProcessBuilder pb = new ProcessBuilder(
    dir + "library/crc",
    "-s",
    fileName,
    addressRanges);

If you could take the time to read the docs you would know this. A ProcessBuilder can start multiple processes. (Sort of the point of having a ProcessBuilder.)