Adds a readme for the shell

Author: arcanis

packages/berry-shell/README.md

@@ -0,0 +1,29 @@
+# `@berry/shell`
+
+A Javascript implementation of a bash-like shell (we use it in Yarn 2 to provide cross-platform scripting). This package contains the parser and interpreter merged together; for the parser only you can check the `@berry/parsers` package, but you probably won't need it.
+
+## Usage
+
+```ts
+import {execute} from '@berry/shell';
+
+process.exitCode = await execute(`ls "$1" | wc -l`, [process.cwd()]);
+```
+
+## Features
+
+- Typechecked
+- Portable across systems
+- Supports custom JS builtins
+- Supports pipes
+- Supports logical operators
+- Supports subshells
+- Supports variables
+- Supports string manipulators
+- Supports argc/argv
+- Supports the most class builtins
+- Doesn't necessarily need to access the fs
+
+## Help Wanted
+
+- Stream redirections (`> foo`)