Even if someone is a regex guru there are times that people get confused with some regular expression and want to either test it out or want to some help. Behold, redet is here. Lets start with installing redet:
sudo yum install redet
Once you are done with installation, just run it with redet. First you need to load the sample data, select your program and then enter the regex to test it out. Here are some screenshots to get you started.