scheme Scsh has two main components: a process notation for running programs and setting up pipelines and redirections, and a complete syscall library for low-level access to the operating system, i.e. to POSIX, the least common denominator of more or less all Unices, plus widely supported extensions such as symbolic links and BSD sockets. Moreover, scsh provides an awk facility for pattern-directed computation over streams of records, a rich facility for matching regular-expression patterns in strings, event-based interrupt handling, user-level threads, a futuristic module system, and an interactive environment. Scsh comes with extensive documentation describing these and other features.