sub exec {
  my ($comm) = @_;
  
  if ( dbg::debugOn() ) {
    dPrt("dbg","Debug, Would execute:\n$comm");
  } else {
    dPrt("libs_verbose","Executing:$comm");
    system("$comm");
    if ($? == -1) {
      throw err("system command returned -1: $comm\nReason $!");
    }
    elsif ($? & 127) {
      my ($sSig) = $? & 127;
      throw err("Command died with signal $sSig :$comm");
    }
    else {
      my ($nExitVal) = $? >> 8;
      if ( $nExitVal != 0 ) {
  	    throw err("Command exited with value $nExitVal :$comm");
      }
    }
  }