NodeJS provides APIs for executing shell commands, however which shell invokes these commands depends on your OS. There is no universal shell interpreter that is guaranteed to be installed on every PC with Linux, Mac, or Windows.
Unfortunately each shell has its own opinions about:
- Which characters are "special" and need to be escaped?
- How do you escape a special character?
- Is "/" or "" the path separator?
- What's the syntax for substituting an environment variable?
The Rushell library provides a minimal subset of a POSIX-compatible shell, implemented in pure JavaScript, and guaranteed to behave consistently on every platform. Rushell does not aim to be an interactive command prompt or Turing-complete language. It's merely a reliable cross-platform solution for very basic needs such as:
- Invoke a tool with command-line arguments
- Reliably quote special symbols
- Chain multiple commands using
&&or|| - Use
cdto change the current working directory - Expand environment variables
(These are the requirements that Rush had when invoking lifecycle scripts from a package.json file.)
Invoking a script using Rushell should generally provide similar output as dash. Only a small subset of POSIX shell features are supported. More can be added over time, although the overall aim is to remain simplistic, lightweight, and self-contained (i.e. no dependencies on other libraries).
Example shell scripts:
echo "Hello, world" - print a string containing a space