# Filters
Filters let another program process the text inside them. You could, for example, write Sass or SCSS in your template and use a filter to compile it to regular CSS to be included when the template is rendered.
Filters are implemented through commands just as you would run them in a terminal. The content of the filter is given to the command through stdin and it's unescaped stdout is put in the template.
{% hint style="info" %}
Filters are processed during compile time. Hence, you cannot use interpolation in them and you won't need to escape any `#`.
{% endhint %}
You can also give space-separated arguments to the command. Just like in the shell, you may enclose arguments in strings which will be parsed like regular Go strings using `strconv.Unquote`.
{% hint style="danger" %}
Executing arbitrary commands poses a security risk (Imagine someone used `rm -rf --no-preserve-root /` as a filter).
While you should of course always vet what `go generate` executes, it is always better to be safe than sorry. Hence, **corgi will only run filters previously approved.**
You can approve a filter by specifying it in the `-trusted-filter` flag.
On Linux, macOS, and Windows, you can also use `corgi -edit-trusted-filters` to start an editor to edit a list of user-wide trusted filters, or directly open `$HOME/.config/corgi/trusted_filters` or `%AppData%\Local\corgi\trusted_filters`.
If you trust the template you are running (or just don't care if someone steals your bank details ;)), you can set the `-trust-all-filters` flag to `i know this is dangerous` to allow all filters to be run.
{% endhint %}
{% tabs %}
{% tab title="Corgi" %}
```pug
style
//- https://sass-lang.com
:sass --stdin
nav
ul
margin: 0
padding: 0
list-style: none
li
display: inline-block
```
{% endtab %}
{% tab title="HTML" %}
```markup
```
{% endtab %}
{% endtabs %}
## The Built-In Raw Filter
If you don't specify any command, corgi will write the contents verbatim to the document. This is useful, if you want to include an HTML snippet like an svg, without the hassle of converting it to corgi-syntax.
It is equivalent to using `:tee`, except that it doesn't require `tee` to be installed on the system.
You don't need to approve the raw filter, it is always available.
{% tabs %}
{% tab title="Corgi" %}
```pug
p Look at my cool icon:
p
:raw
```
{% endtab %}
{% tab title="HTML" %}
```markup
Look at my cool icon:
```
{% endtab %}
{% endtabs %}
### Minification
The Raw Filter can also minify HTML, SVGs, JavaScript, and CSS. Simply write `html`, `svg`, `js`, or `css` behind the filter to enable it.
{% tabs %}
{% tab title="Corgi" %}
```pug
p
:raw svg
```
{% endtab %}
{% tab title="HTML" %}
{% code overflow="wrap" lineNumbers="true" %}
```markup
```
{% endcode %}
{% endtab %}
{% endtabs %}