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About java : ProcessBuilder-redirecting-output

Question Detail

I am trying to redirect output of a process started with the help of ProcessBuilder using 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 with 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)

It works fine when I just pass “/myScript”

Script is perl, any suggestions/coments on why it is failing?

I tried passing all of them as seperate arguments like new ProcessBuilder("/myScript",">>","/myLogFile"), it executes but it does not redirect to log file and also it does not take envVars.

Question Answer

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

As you specified, from Java7 you can keep using ProcessBuilder with the only executable file as parameter and redirect/intercept its output stream, using redirectInput() redirectOutput() and redirectError() from ProcessBuilder class.

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