shell Command execution Failing when executed from Java

Question

When I execute the below command on command line, it shows all the stored procedures and tables in the sybase DB.

printf 'sp_help\ngo\n' | isql -Uxx -Pxxxx -Dxxxxx

But when I do the same thing in java. This does not return any result. Can anyone tell me what is the problem with my code below:

public class test
{
  public static void main(String[] args)
  {
   String cmd = "printf "+"\'sp_help\ngo\n\'"+"| isql -Uxx -Pxxxx -Dxxxxx" ;
   try{ 
          Process p;
          p = Runtime.getRuntime().exec(cmd);
          p.waitFor();
          String line; 
          BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));

           while ((line = reader.readLine())!=null){
           System.out.println("Row is :" + line);
   } catch(Exception e)
       {
           System.out.println("Exception Caught : " + e);
       }

  }

}

EDIT I executed it as below suggested by Darkdust but still it doesnt work.

try{
          Process p;
          p = Runtime.getRuntime().exec("sh -c \'printf \"sp_help\ngo\n\" | isql -Uxx -Pxxxxx -Dxxxxxx\'");
          p.waitFor();
          String line;
          BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));

           while ((line = reader.readLine())!=null){
           System.out.println("Row is :" + line);
  }
 }
       catch(Exception e)
       {
           System.out.println("Exception Caught : " + e);
       }

But the command :

sh -c 'printf "sp_help\ngo\n" | isql -Usa -Psybase11 -Dcnadb'

Works on command line.

I also tried with :

p = Runtime.getRuntime().exec(new String[]{"sh","-c","\'printf \"sp_help\ngo\n\"","|isql -Uxx -Pxxxxx -Dxxxxx\'"});

But with no sucess.

DarkDust · Accepted Answer · 2013-08-06 13:12:46Z

1

Several things come to mind:

Incomplete PATH environment variable (thus isql can't be found).
If it's a command you provide, instead of messing with PATH you might want to make sure your are you in the correct working directory and call ./isql instead.
Since you're using a pipe, you should let a shell execute this as in sh -c "foo | bar". Otherwise the | isql ... part is passed as argument to printf as well.

answered Aug 6, 2013 at 13:12

DarkDust

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6 Comments

user1939168 Over a year ago

isql PATH is available. As i said that the command runs as expected from command line. Why the same is not running as expected in java? And i think the whole cmd will be executed on command line and output will be retrieved into java

DarkDust Over a year ago

See my last point. Java might run "printf" and pass everything as arguments to "printf", even the pipe symbol and everything afterwards. You need to run a shell and let that run your command, as in sh -c "printf 'sp_help\ngo\n' | isql -Uxx -Pxxxx -Dxxxxx". You probably want to use the exec variant with an String[] argument: IIRC, it should be Runtime.getRuntime().exec(new String[]{"sh", "-c", cmd}); (my Java is rusty).

user1939168 Over a year ago

OK.. I got your point. But the problem now i am facing is sh -c "printf "sp_help\ngo\n" | isql -Uxx -Pxxx -Dxxxxx" is not working on the command line itself if i add sh -c as prefix to the command.It gives me an error Usage: printf format [argument...]

DarkDust Over a year ago

No, I do not mean to write a bash script. On the shell, you would need to enter sh -c 'printf "sp_help\ngo\n" | isql -Uxx -Pxxx -Dxxxxx' (or use " and escape them inside with \"). Most likely all you need to do is replace your p = ... line with p = Runtime.getRuntime().exec(new String[]{"sh", "-c", cmd}); (in this case no extra " escaping is necessary). Have you tried that?

Daniel Gerber Over a year ago

Did you happen to fix the issue?

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