or download this
my @options = qw(
...
$config->{result_filename} =~ s{ }{\\ }g;
my $command = "(" . join(" ", $config->{wkhtmltopdf_path}, @options, $
+source_file, $config->{result_filename}) . ")";
system( "/bin/bash -c \"$command\" >/dev/null 2>&1" );