pipe Unix commands together in Java

Question

I have a requirement to run the below command from Java

echo <inputMessage> | iconv -f utf8 -t Cp930

When i use the below code to run the command i see only the echo part is executed but the piping is not happening

public static String callInconverter2(String input,String codePage) throws IOException {
        try{
        //  String command = "echo asdasdasd | iconv -f UTF-8 -t Cp930";
            Process p = Runtime.getRuntime().exec("echo "+input+"| iconv -f UTF-8 -t "+codePage);
        String s = null;
        BufferedReader stdInput = new BufferedReader(new 
                 InputStreamReader(p.getInputStream()));

            BufferedReader stdError = new BufferedReader(new 
                 InputStreamReader(p.getErrorStream()));
            StringBuilder sb = new StringBuilder();
            // read the output from the command
            System.out.println("Here is the standard output of the command:\n");
            while ((s = stdInput.readLine()) != null) {
                sb.append(s);
            }

            // read any errors from the attempted command
            System.out.println("Here is the standard error of the command (if any):\n");
            while ((s = stdError.readLine()) != null) {
                sb.append(s);
            }
            return sb.toString();

        }
        catch (IOException e) {
            System.out.println("exception happened - here's what I know: ");
            e.printStackTrace();
            return e.getMessage();
        }
            }}

I am new to Runtime. is there anything am missing.

Tried the method suggested by thomas

String command = "echo asdasdasd | iconv -f UTF-8 -t Cp930";
Process p = Runtime.getRuntime().exec("bash -c \""+command+"\"");

was getting an error asdasdasd: -c: line 0: unexpected EOF while looking for matching `"'asdasdasd: -c: line 1: syntax error: unexpected end of file

is there anything am missing out

Thomas W · Accepted Answer · 2013-05-16 05:54:45Z

3

Run a shell, with that command -- bash, tcsh, whichever one you normally use.

bash -c "echo | iconv -f utf8 -t Cp930"                 // or
bash -lc "echo | iconv -f utf8 -t Cp930"

Piping is a shell functionality.

Thus:

Runtime rt = Runtime.getRuntime();
String cmd = "echo | iconv -f utf8 -t Cp930";
rt.exec("bash -c \""+cmd+"\"");

See the bash manual for invocation options. http://www.gnu.org/software/bash/manual/html_node/Invoking-Bash.html#Invoking-Bash

edited May 16, 2013 at 5:54

answered May 16, 2013 at 5:48

Thomas W

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2 Comments

VamsiKrishna Over a year ago

tried the above way String command = "echo asdasdasd | iconv -f UTF-8 -t Cp930"; Process p = Runtime.getRuntime().exec("bash -c \""+command+"\""); was getting an error as asdasdasd: -c: line 0: unexpected EOF while looking for matching `"'asdasdasd: -c: line 1: syntax error: unexpected end of file Anything i missed out

Thomas W Over a year ago

Looks like it might be something about quoting, just debug it starting from the basics of a simple bash invocation & making sure the command runs from an interactive shell.

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