# Description
Instead of returning an error, this PR changes `expand_glob` in
`run_external.rs` to return the original string arg if glob creation
failed. This makes it so that, e.g.,
```nushell
^echo `[`
^echo `***`
```
no longer fail with a shell error. (This follows from #12921.)
These sub-crates form both the foundation for Nu and a set of plugins which extend Nu with additional functionality.
Foundational libraries are split into two kinds of crates:
Core crates - those crates that work together to build the Nushell language engine
Support crates - a set of crates that support the engine with additional features like JSON support, ANSI support, and more.
Plugins are likewise also split into two types:
Core plugins - plugins that provide part of the default experience of Nu, including access to the system properties, processes, and web-connectivity features.
Extra plugins - these plugins run a wide range of different capabilities like working with different file types, charting, viewing binary data, and more.