How do I test if my regex will work?

I am trying to get a regular expression to match against some known input and I want a low-friction way to test it out without writing a full-blown application test. How do?

For Elixir, try http://elixre.lpil.uk or https://www.elixirregex.com.

For Ruby, try https://rubular.com.

For JavaScript (and PHP), try https://regexr.com.

They all show the options you can try with the regex and commonly used regex syntax.

With rubular and elixirregex, you can also share the regex, options, and input you used with a permalink.

With regexr, you can save regex for later as well access community regex patterns.