MY.cgi
 my $xslt = XML::LibXSLT->new();
 my $stylesheet = $xslt->parse_stylesheet_file('abc.xsl'); 
 push @xsltParams, ('arg', $str);
 push @xsltParams, ('val', '1');
 my $result = $stylesheet->transform_file('abc.xml', @xsltParams);
 print $stylesheet->output_string($result);

##</code><code>##

MY.xsl
 <xsl:value-of select="$arg"/>