Directives are functional keywords that appear within site [blocks](/docs/caddyfile/concepts#blocks). Sometimes, they may open blocks of their own which can contain _subdirectives_, but directives **cannot** be used within other directives unless noted. For example, you can't use `basicauth` inside a `file_server` block, because `file_server` does not know how to do authentication. However, you _may_ use some directives within special directive blocks like `handle` and `route` because they are specifically designed to group HTTP handler directives.
Most—but not all—directives accept [matcher tokens](/docs/caddyfile/matchers#syntax), which let you filter requests. Matcher tokens are usually optional. Directives support matchers if you see this in a directive's syntax:
Because matcher tokens all work the same, the various possibilities for the matcher token will not be described on every page, to reduce duplication. Instead, refer to the [matcher documentation](/docs/caddyfile/matchers) for a detailed explanation of the syntax.
Many directives manipulate the HTTP handler chain. The order in which those directives are evaluated matters, so a default ordering is hard-coded into Caddy.
You can override/customize this ordering by using the [`order` global option](/docs/caddyfile/options#order) or the [`route` directive](/docs/caddyfile/directives/route).
For ease of use, the Caddyfile adapter sorts directives according to the following rules:
- Differently named directives are sorted by their position in the [default order](#directive-order#order). The default order can be overridden with the [`order` global option](/docs/caddyfile/options).
- Same-named directives are sorted according to their [matchers](/docs/caddyfile/matchers#syntax).
- The highest priority is a directive with a single [path matcher](/docs/caddyfile/matchers#path-matchers).
Path matchers are sorted by specificity, from most specific to least specific.
In general, this is performed by sorting by the length of the path matcher. There is one exception where if the path ends in a `*` and the paths of the two matchers are otherwise the same, the matcher with no `*` is considered more specific and sorted higher.
For example:
-`/foobar` is more specific than `/foo`
-`/foo` is more specific than `/foo*`
-`/foo/*` is more specific than `/foo*`
- A directive with any other matcher is sorted next, in the order it appears in the Caddyfile.
This includes path matchers with multiple values, and [named matchers](/docs/caddyfile/matchers#named-matchers).
- A directive with no matcher (i.e. matching all requests) is sorted last.
- The [`vars`](/docs/caddyfile/directives/vars) directive has its ordering by matcher reversed, because it involves setting values which can overwrite eachother, so the most specific matcher should be evaluated last.
- The contents of the [`route`](/docs/caddyfile/directives/route) directive ignores all the above rules, and preserves the order the directives appear within.
