yarnpkg-shell

@yarnpkg/shell

A JavaScript implementation of a bash-like shell (we use it in Yarn 2 to provide cross-platform scripting). This package exposes an API that abstracts both the parser and the interpreter; should you only need the parser you can check out @yarnpkg/parsers, but you probably won't need it.

Usage

import {execute} from '@yarnpkg/shell';

process.exitCode = await execute(`ls "$0" | wc -l`, [process.cwd()]);

Features

• Typechecked
• Portable across systems
• Supports custom JS builtins
• Supports pipes
• Supports glob patterns (only for files that exist on the filesystem: ls *.txt)
• Supports logical operators
• Supports subshells
• Supports variables
• Supports string manipulators
• Supports argc/argv
• Supports background jobs with color-coded output
• Supports the most classic builtins
• Doesn't necessarily need to access the fs

Help Wanted

• Full glob support (mv build/{index.js,index.build.js}, echo {foo,bar}, FOO=a,b echo {$FOO,x})
• More string manipulators

Non-Goals

• Perfect POSIX compliance (basic scripting is enough for now)
• Multiline scripts (we mostly target one-liners)
• Control structures (same reason)