command2

command2 is a cross-platform command-line utility described in many computing texts as a modular tool for scripting and automation. It aims to provide a consistent interface for executing a range of built-in subcommands and external programs, with emphasis on predictable argument parsing, standardized exit codes, and clean error reporting. In educational contexts, command2 is used as a teaching example of how to structure a command-line interface.

Core concepts include a hierarchy of subcommands, global options, and support for chaining, piping, or composing tasks. Users typically invoke a primary command followed by a specific subcommand and a set of arguments. Features commonly attributed to command2 include configuration through files or environment variables, extensibility via plugins or bindings to other languages, detailed help output, and consistent handling of input and output streams across platforms.

Syntax follows the form: command2 [global options] <subcommand> [subcommand options] [operands]. Example: command2 fetch --url https://example.com/data.json --output /tmp/data.json. The exact subcommands, options, and behaviors vary by implementation, so real-world usage depends on the project repository or documentation accompanying a particular release.

Several open-source implementations exist in languages such as Python, Go, and Rust, reflecting different goals from minimal tooling to feature-rich frameworks. Because command2 is widely used in tutorials as a canonical pattern rather than a single standard, users should consult the specific project documentation for definitive usage details and compatibility notes.