Help! How to call Unix system command?

Question

In my java application.there are some code as following:
try{
String cmd = "ls -a > temp.txt";
Runtime runtime = Runtime.getRuntime();
Process process = runtime.exec(cmd);
int rc = process.exitValue();
if (rc == 0){
System.out.println("OK!");
else{
System.out.println("Failed!");
catch(Exception ex){
ex.printStackTrace();
But when i run the application, it always throws IllegalTreadStateException,
return code(rc) is 2, exception's content is as below:
java.lang.IllegalThreadStateException: process hasn't exited
at java.lang.UNIXProcess.exitValue(UNIXProcess.java:118)
at MyApplication.main(...)
If someone know what happened, please help me, my E-mail address is:
[email protected]

Answer 1

import java.io.*;
public class RunCommand {
public static void main(String args[]) {
String s = null;
try {
     // run the Unix "ps -ef" command
Process p = Runtime.getRuntime().exec("ps -ef");
BufferedReader stdInput = new BufferedReader(new
InputStreamReader(p.getInputStream()));
BufferedReader stdError = new BufferedReader(new
InputStreamReader(p.getErrorStream()));
// read the output from the command
System.out.println("Here is the standard output of the command:\n");
while ((s = stdInput.readLine()) != null) {
System.out.println(s);
// read any errors from the attempted command
System.out.println("Here is the standard error of the command (if any):\n");
while ((s = stdError.readLine()) != null) {
System.out.println(s);
System.exit(0);
catch (IOException e) {
System.out.println("exception happened - here's what I know: ");
e.printStackTrace();
System.exit(-1);
http://www.devdaily.com/java/edu/pj/pj010016/index.shtml
Cheers,
Bala