RewriteCond %{REQUEST_URI} !\.(jpe?g|png|gif|css|js)
# rewrite if the given string is not an already existing file
RewriteCond %{REQUEST_FILENAME} !-f
# rewrite if the given string is not an existing directory
RewriteCond %{REQUEST_FILENAME} !-d
# rewrite to Lanas.pl with QUERYSTRING appended
RewriteRule (.*)(/(.*))? /cgi-bin/Lanas.pl?$1=$3

RewriteRule ^/?$ /cgi-bin/Lanas.pl