How to execute multiple commands in a single terminal using Java?

Question

try
{
    Runtime rt =  Runtime.getRuntime();
    rt.exec("cmd /c start cmd.exe /K \"java -version\"");
    System.out.println("After completing the first command");
    rt.exec("cmd /c start cmd.exe /K \"javac -version\""); 
}
catch (Exception e)
{
    System.out.println("Something wrong");
    e.printStackTrace();
}

By using the above program I am able to execute commands in a terminal, but it opens multiple instances of the terminal. I want to execute both commands in the same terminal. Is this possible?

I'm not a MS Windows genius but you start multiple command prompts with start cmd.exe or? — Constantin Müller
– Constantin Müller, Commented Apr 23, 2018 at 13:42
Can't you simply write a batch that executes the 2 commands one after the other? From within your JVM you should then simply launch that batch. — Robert Kock
– Robert Kock, Commented Apr 23, 2018 at 13:44

C.Champagne · Accepted Answer · 2018-04-23 13:59:48Z

2

As suggested, you can put your commands in a .bat file that you will run from java program or you can use the & or the && operator.

(The difference between the two operators is that && will let the second command be executed only if the first succeeded.)

Try this:

rt.exec("cmd /c start cmd.exe /K \"java -version && javac -version\"");

answered Apr 23, 2018 at 13:59

C.Champagne

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3 Comments

OneCricketeer Over a year ago

"cmd /c start cmd.exe" isn't really necessary if you want to run in the existing cmd session

Chandrakanth Over a year ago

yes that can be done by using && operator. but i just wanted some operations before executing second command. after performing some operations i want to execute second command in the previously opened command line.

C.Champagne Over a year ago

@Chandrakanth, why don't you start your Java app in a terminal and just print the result in a standard output?

wandermonk · Accepted Answer · 2018-04-23 14:37:24Z

1

You could also use a ProcessBuilder java API to do this. By default Runtime.getRuntime().exec will tokenize the input, in the case of ProcessBuilder it will execute the command as it is.

public class TestCommands {

    public static void main(String[] args) throws IOException, InterruptedException {

        String[] commands = {"echo hello","echo hi","java -version"};

        for(String command : commands) {
            execute(command);
        }
    }


    public static void execute(String command) throws InterruptedException, IOException {
        ProcessBuilder builder = new ProcessBuilder("cmd.exe","/c",command);
        Process process = builder.inheritIO().start();
        process.waitFor();

        BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
        String readline;
        while ((readline = reader.readLine()) != null) {
            System.out.println(readline);
        }
    }
}

answered Apr 23, 2018 at 14:37

wandermonk

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1 Comment

Jesse Jashinsky Over a year ago

I've tried this code in a unit test, but the output is going to my output screen, not the BufferedReader. Do you know why this is?

Macintosh Fan · Accepted Answer · 2022-08-08 19:28:54Z

If anyone is looking for a solution for macOS, I made one:

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

public class CustomDesktop {
    public static void main(String[] args) throws IOException, InterruptedException {
        // Execute multiple commands in one terminal.
        final String[] TERMINAL_COMMANDS = {"cd ~/Videos", "ls -l"};

        StringBuilder command = new StringBuilder(); // Using StringBuilder is recommended: less memory and faster.
        for (String terminalCommand : TERMINAL_COMMANDS) {
            command.append(terminalCommand).append(';');
        }
        execute(command.toString());

        // Direct method call, if you prefer.
        execute("cd ~/Videos; ls -l");
    }

    public static void execute(String command) throws IOException, InterruptedException {
        // Use "bash" instead if your Mac runs pre-Catalina.
        ProcessBuilder builder = new ProcessBuilder("zsh", "-c", command);
        Process process = builder.inheritIO().start();
        process.waitFor();

        BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
        String readline;
        while ((readline = reader.readLine()) != null) {
            System.out.println(readline);
        }
    }
}

Output:

total 539296
-rw-r--r--@ 1 macintoshfan  staff  276116282 Jun 18 14:14 Java.mov
total 539296
-rw-r--r--@ 1 macintoshfan  staff  276116282 Jun 18 14:14 Java.mov

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