Thanks for your reply. I found some sample code on the web that uses IPC::Open3 and used it in my program. Is it requirs to write data to the WRITE descriptor before I can read from it? My binary writes data to STDOUT/STDERR first, and then reads STDIN. 
sub ExecCmd
{
   my $cmd = shift;
   my $pid = open3(\*WRITE,\*READ,\*ERROR,$cmd);
   unless (defined $pid) {
      LogError("Failed to execute $cmd");
      return undef;
   }
   LogInfo("PID is $pid");
   my $select = new IO::Select();
   $select->add(\*READ);
   $select->add(\*ERROR);

   foreach my $handle ($select->can_read) {
      LogInfo("handle is $handle");
      my $buf = "";
      if($handle eq \*ERROR) {
         sysread(ERROR,$buf,BUFFER);
         close ERROR;
         if($buf) {
            LogInfo("ERROR -> $buf");
         }
      } else {
         sysread(READ,$buf,BUFFER);
         close READ;
         if($buf) {
            LogInfo("READ -> $buf");
         }
      }
   }
   print WRITE "0\n";

[download]
In the above, the program seems to be waiting for some kind of input after it prints the PID - never enters the foreach loop. How can I solve the above problem?

Thanks!

In reply to Re^2: Executing command from perl script with input/output by linuxfan
in thread Executing command from perl script with input/output by linuxfan

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