Websites/tools supporting Regular Expression check & generate

During working with .htaccess file (RewriteRule) I found these tools useful for checking & generating RegExpression http://martinmelin.se/rewrite-rule-tester/ http://htaccess.madewithlove.be/ http://regexpal.com/ http://txt2re.com/index.php3?s=http://localhost:8282/images/dvd/index.php&-8&-16 http://gskinner.com/RegExr/