How do I redirect from a legacy category URL to a new catgory URL using Retour I've installed the Retour plugin and have been able to get most of my redirects working, but have now run into a situation where the old site had multi-level category hierarchy eg: /category/category-slug/sub-category-slug url structure and the new site only has a single level eg: /news/category/category-slug

How can I create a Regex to grab the last segment off the url, if there is more than one level of category, to use for my redirect ? 

Looks like if there was only one level then the following would do: 

/category/* to /news/category/$1 

Any tips or ideas ?
Despite having used regex's for years, I still almost never get them right from memory. A great tool for testing them out is: https://regexr.com/

What you'll need to use is a capture group. Something like this for the source:

/category/(.*$)

And then the resulting URI would be something like this:

/news/category/$1

Each set of () is a capture group; they are numbered sequentially, so $1 will output the first capture group.

If you go to https://regexr.com/ it will even explain every part of the regex, and what it does: