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  1. In Java, how do I execute a linux program with options, like this:

    ls -a (the option is -a),

    and another: ./myscript name=john age=24

    I know how to execute a command, but cannot do the option.

latonz
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Simo
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2 Answers2

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You need to execute an external process, take a look at ProcessBuilder and just because it almost answers your question, Using ProcessBuilder to Make System Calls

UPDATED with Example

I ripped this straight from the list example and modified it so I could test on my PC and it runs fine

private static void copy(InputStream in, OutputStream out) throws IOException {
    while (true) {
        int c = in.read();
        if (c == -1) {
            break;
        }
        out.write((char) c);
    }
}

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

//        if (args.length == 0) {
//            System.out.println("You must supply at least one argument.");
//            return;
//        }

    args = new String[] {"cmd", "/c", "dir", "C:\\"};

    ProcessBuilder processBuilder = new ProcessBuilder(args);
    processBuilder.redirectErrorStream(true);

    Process process = processBuilder.start();
    copy(process.getInputStream(), System.out);
    process.waitFor();
    System.out.println("Exit Status : " + process.exitValue());
}
MadProgrammer
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  • I am aware if ProcessBuilder, but kinda struggling with it. Any concrete example? How would you set the String array in the contructor of ProcessBuilder? `ProcessBuilder pb = new ProcessBuilder(.......)` How to I set command and args inside the dot dot dot? – Simo Aug 09 '12 at 23:39
  • I'd have a read of the example, it literally does what you want. `ProcessBuilder` takes either a `List` or array of `String` arguments, the first is the command to be executed, the remainder at the command parameters (each one should be a separate parameter) – MadProgrammer Aug 09 '12 at 23:45
  • You might also like to have a read of http://stackoverflow.com/questions/1410741/want-to-invoke-a-linux-shell-command-from-java for executing shell commands – MadProgrammer Aug 09 '12 at 23:46
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Apache Commons has a library built to handle this type of thing. I wish I knew about it before I coded something like this by hand. I found it later on. It takes options in various formats for a command line program.

Apache Commons CLI

Logan
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