$cmd = wfEscapeShellArg( $wgDjvuDump ) . ' ' . wfEscapeShellArg( $this->mFilename );
$dump = wfShellExec( $cmd );
$xml = $this->convertDumpToXML( $dump );
$cmd = wfEscapeShellArg( $wgDjvuDump ) . ' ' . wfEscapeShellArg( $this->mFilename );
$dump = wfShellExec( $cmd );
$xml = $this->convertDumpToXML( $dump );