Most existing gems that address command execution provide a limited interface or lack notable features. In contast, Exek seeks to provide comprehensive support for all of a program's exec needs with one thoughtfully-designed library. Intended features: - A "Command" class that encapsulates argv, env, and IO options, and process state. - Easy-to-use high level interfaces with sensible defaults for running commands to completion. - Comprehensive support for low-level concerns like piping, PTYs, and file descriptor magic. - Utilities for manipulating `sh` script strings, idiomatically building argument arrays, and generating reusable interaces for common system commands. - Tracing and introspection facilities for logging and latency analysis. - Safety: does not monkeypatch external modules, encourage mixins or use eval. Attempts to guide developers away from unsafe practices like shell scripts and shell injection.