Re: exec() and sending to STDIO and reading from STDIO

From:
WinstonSmith_101@hotmail.com
Newsgroups:
comp.lang.java.programmer
Date:
18 Oct 2006 04:30:31 -0700
Message-ID:
<1161171031.573547.305540@m73g2000cwd.googlegroups.com>
Gordon Beaton wrote:

On 18 Oct 2006 00:46:36 -0700, WinstonSmith_101@hotmail.com wrote:

Hello thanks for the feedback, but this merely echos out "foo | gurka".


No, it doesn't. Post your *actual* code. You are not running a shell
as I suggested.

This is what happens when I run it with real commands:

  bash$ cat Test.java
  import java.io.*;

  public class Test {
    public static void main(String[] args) throws Exception {
      String[] cmd = { "/bin/sh", "-c", "echo this is a test | wc" };
      Process p = Runtime.getRuntime().exec(cmd);

      BufferedReader br = new BufferedReader(new InputStreamReader (p.getInputStream()));

      String line;
      while ((line = br.readLine()) != null) {
        System.out.println(line);
      }
      br.close();
    }
  }

  base$ javac Test.java
  bash$ java Test
        1 4 15
  bash$

The example is complete and compilable. Try it.


- your example works. But when I substitude the program gpg for wc, I
stop getting the output. Can it be that it sends on STDERR or
something?

import java.io.*;

public class Test1
{
    public static void main(String[] args) throws Exception
    {
        String[] cmd = { "/bin/sh", "-c", "echo mypasswd | gpg
--passphrase-fd 0 -o tobe.zip -q --decrypt tobe.zip.gpg" };

        Process p = Runtime.getRuntime().exec(cmd);

        BufferedReader br = new BufferedReader(new InputStreamReader
(p.getInputStream()));

        String line;
        while ((line = br.readLine()) != null)
        {
            System.out.println("XXX: " + line);
        }

        br.close();
    }
}

- it's the same. I just changed the "String[] cmd =" line

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