A java library of common unix commands (specifically dd)?

I need to use the dd command for blocking some files, and would rather do 开发者_高级运维it without calling it via shell.

Is there a class library already written, or should I roll my own blocker unblocker?

Basically equivalent to going:

dd if=foo.log of=fooblocked.log cbs=79 conv=block

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Runtime.getRuntime().exec() executes the command passed in a shell (a command prompt in Windows) the shell defaults to the programs working directory.

try {
     Process p = Runtime.getRuntime().exec("ls -l");
     BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
     String str = br.readLine();
     while(str!=null) {
         System.out.println(str);
         str=br.readLine();
     }
}

If you need the program to wait until the command completes, you can use p.waitFor().