Using ?: after opening parenthesis of a capturing group creates a non-capturing group. Useful for example with template function reFindAllSubmatches.

This will not sub-match the words "red, blue, green": {{ refindAllSubmatches `color=(?:red|blue|green)` .Message.Content }}

You may also want to catch multiple options, for that we use a "Vertical bar" or also known as a "Pipe" between linux users.

As example, this will match if either "Cat" or "Dog" is present: (Cat|Dog)

For matching characters there are multiple options:

Matching specific characters:

For matching a specific character, you put them in square brackets.

This will match A, B and C: ([abc])

This will match every character from a-Z: ([a-Z])

This will match every number: ([0-9])

Sometimes you have to use special characters but it may cause conflicts. In this case, you will have to use an escape character.

For example, this is a star that doesn't interfere with other matches \*.