Linux中未捕获linux命令的输出

Question

I am trying to run the below command from java and want to capture the output. The method is getting completed immediately without writing anything to the console.

Linux Command is repo forall -c 'echo pwd is;pwd;git status' and the method is

public static String executeCommandWithOutput(String command) {
    System.out.println("Running the command "+command);
    StringBuffer output = new StringBuffer();
    String line = "";
    try {
        Process process =Runtime.getRuntime().exec(command);
        process.waitFor();

        BufferedReader reader = 
            new BufferedReader(new InputStreamReader(process.getInputStream()));
        while ((line = reader.readLine())!= null) {
            output.append(line);
        }
        System.out.println("Content is "+output.toString());
    } catch (IOException e) {
        e.printStackTrace();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    return output.toString();
}

I tried redirecting the output to a file as well. Neither worked. Any thoughts??

Answer 1

Check if the command your are trying to execute has a standard output.

Probably its failing and you are getting error output.

You can check the error output with getErrorStream , documentation is here .

Eg like this

StringBuffer error = new StringBuffer();

BufferedReader reader = 
    new BufferedReader(new InputStreamReader(process.getErrorStream()));

while ((line = reader.readLine())!= null) {
        error.append(line);
}

System.out.println("Error is " + error.toString());

Also check the exitValue of your forked command, doc is here

int exitStatus = process.exitValue();

System.out.println("Exit status is " + exitStatus );