* Hugo has a virtual file system and only the main project (not third-party components) is allowed to mount directories or files outside the project root.
* Only the main project can walk symbolic links.
* User-defined components have only read-access to the filesystem.
-* We shell out to some external binaries to support [Asciidoctor](/content-management/formats/#list-of-content-formats) and simliar, but those binaries and their flags are predefined. General functions to run arbitrary external OS commands have been [discussed](https://github.com/gohugoio/hugo/issues/796), but not implemented because of security concerns.
+* We shell out to some external binaries to support [Asciidoctor](/content-management/formats/#list-of-content-formats) and similar, but those binaries and their flags are predefined. General functions to run arbitrary external OS commands have been [discussed](https://github.com/gohugoio/hugo/issues/796), but not implemented because of security concerns.
Hugo will soon introduce a concept of _Content Source Plugins_ (AKA _Pages from Data_), but the above will still hold true.