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Thread: why is terminal not returning results to ide

  1. #1
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    Default why is terminal not returning results to ide

    hi i am trying to run a command in terminal the code is below if i run the command in terminal it works fine however when i run it from netbeans with code below nothing gets printed. however if i run a different command such as (ip addr) it works fine any ideas on why?

    public static void a() throws IOException{
                ArrayList lister=new ArrayList();
                Runtime rt = Runtime.getRuntime();
                Process proc = rt.exec("ps -ef | grep firefox");// the command i am trying to run to get pid of application
                InputStream stderr = proc.getInputStream();
                InputStreamReader isr = new InputStreamReader(stderr);
                BufferedReader br = new BufferedReader(isr);
                String line;
                while ( (line = br.readLine()) != null){
                    lister.add(line);
                }
                for(int y=0;y<lister.size();y++){
                    System.out.println(lister.get(y));
                }
        }


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    Default Re: why is terminal not returning results to ide

    Pipe's have issues. Three options:
    a) Execute directly with a shell (eg sh -c "ps -ef | grep firefox")
    b) write a shell script and call that script directly
    c) Do the commands one at a time, using the Input/Output streams to manually pipe the results of one to another.

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    Default Re: why is terminal not returning results to ide

    Note that for option (a) the commands need to be put into a String array, e.g.,
    Process proc = rt.exec(new String[] { "/bin/sh", "-c", "ps -ef | grep firefox" });
     
    // Doesn't work - no output.
    // Process proc = rt.exec("/bin/sh -c \"ps -ef | grep firefox\"");

    Btw I noticed that you had this comment, "the command i am trying to run to get pid of application." Depending on the OS you're using (you should have it if you're using Solaris, Linux or BSD), "pgrep" may be the better command to use.
    Last edited by jashburn; May 14th, 2014 at 09:46 PM. Reason: Add note of pgrep

  4. The Following User Says Thank You to jashburn For This Useful Post:

    bean (May 15th, 2014)

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    Default Re: why is terminal not returning results to ide

    Process proc = rt.exec(new String[] { "/bin/sh", "-c", "ps -ef | grep firefox" });
    this solution worked thanks for replys

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