Build, learn, test regular expressions, with Expresso
Regular expressions isn’t the most difficult thing on earth, yet not anyone knows even basic syntax. Expresso is a free program (with obligatory registration) that includes a library of useful regular expressions you can use to insert automatically parts of an expression you’d like to build, a visual editor.
The program lets you paste expressions to analyze and understand them. It can also run and test your expressions to help you avoid making mistakes that you can’t undo.
If you need to create regular expressions and you are interested in learning more about them, Expresso is an app you should try.