Executing untokenized command line from Java

Question

I am currently using ProcessBuilder to run commands from a java server. This server is to replace an old Perl server, and a lot of our legacy code specifies platform specific command lines.

For instance, on windows it might do:

command -option "hello world"

and on unix it might do:

command -option 'hello world'

The problem is that ProcessBuilder and Runtime.exec both take in tokenized command lines (e.g., {"command", "-option", "hello world"} for both unix and windows).

While I prefer the platform independant way, we have somewhere in the range of 30 million lines of perl code in our codebase. Without me writing a tokenizer for the different platforms (not a big deal really, I just don't want to make a WTF), is there a way to let the shell on the operating system tokenize the command line?

• akuhn: command -option "hello world" works on unix as well, quotes are quotes...
• tster: Regardless, our code does conditionalize on windows vs. unix, usually because the commands are more complex than that and have nested quotes and command line variables and other such nonsense.
• Fantius: 30 million lines of perl?!? I'm so glad I'm not you ;)

Answer 1

Are you able to use the overloaded Runtime.exec(String) that takes a single String and runs that as the entire command?

---

The following works for me on Windows:

Process p = Runtime.getRuntime().exec("perl -e \"print 5\"");
System.out.println(IOUtils.toString(p.getInputStream()));
p.destroy();

---

This is more or less what Runtime.exec(String) is doing:

public static void main(String [] args) throws Exception {
 Process p = new ProcessBuilder(getCommand("perl -e \"print 5\"")).start();
 System.out.println(IOUtils.toString(p.getInputStream()));
 p.destroy();
}
private static String[] getCommand(String input) {
 StringTokenizer tokenizer = new StringTokenizer(input);
 String[] result = new String[tokenizer.countTokens()];
 for (int i = 0; tokenizer.hasMoreTokens(); i++) {
 result[i] = tokenizer.nextToken();
 }
 return result;
}

• Kevin: Is Perl on the path for the environment that the process is executing in?
• tster: Oops, I just realized that I was using ProcessBuilder, not Runtime.exec().
• tster: Is there anyway to use Runtime.exec() without loosing the ability to redirect stderr to stdout?
• Kevin: It doesn't appear so. However, if you look under the covers for Runtime.exec(String), you'll see it is simply using a StringTokenizer to parse the arguments into an array and then passing that to ProcessBuilder. Perhaps you could do something similar

Answer 2

I think the quotes are being interpreted by the shell. Instead, put the command in a shell script:

$ cat temp.sh 
#!/bin/sh
perl -e "print 5"

and execute it:

import java.io.BufferedReader;
import java.io.InputStreamReader;
public class PBTest {
 public static void main(String[] args) {
 ProcessBuilder pb = new ProcessBuilder("./temp.sh");
 pb.redirectErrorStream(true);
 try {
 Process p = pb.start();
 String s;
 BufferedReader stdout = new BufferedReader (
 new InputStreamReader(p.getInputStream()));
 while ((s = stdout.readLine()) != null) {
 System.out.println(s);
 }
 System.out.println("Exit value: " + p.waitFor());
 p.getInputStream().close();
 p.getOutputStream().close();
 p.getErrorStream().close();
 } catch (Exception ex) {
 ex.printStackTrace();
 }
 }
}

Console:

5
Exit value: 0