"Using ProcessBuilder for output redirection"

Question

I'm trying to redirect the output of a process started by ProcessBuilder using the following code:

ProcessBuilder pb = new ProcessBuilder("/myScript >> /myLogFile 2>&1 <& - &");
Map<String, String> env = pb.environment();
env.clear();
env.put("var1", "val1");
env.put("var2", "val2");
pb.redirectErrorStream(true);
Process p = pb.start();

But it failed, throwing exception:

Exception in thread "main" java.io.IOException: Cannot run program "/myScript>> /myLogFile 2>&1 <& - &": java.io.IOException: error=2, No such file or directory at java.lang.ProcessBuilder.start(ProcessBuilder.java:460)

When I just pass "/myScript" it works fine.

The script is perl, any suggestions/comments on why it fails?

I tried passing them as separate parameters like new ProcessBuilder("/myScript",">>","/myLogFile") and it worked, but Will not redirect to log files, nor will envVars be accepted.

Answer 1

According to your requirement, starting from Java7, you can continue to use ProcessBuilder, just pass the executable file as parameter and use redirectInput(), redirectOutput()# in the ProcessBuilder class ## and redirectError() to redirect/intercept its output stream.

Answer 2

The

Shell redirection operator is unknown in ProcessBuilder. Put your command in a shell script and execute it as shown here. Alternatively, use bash -c as shown here.