The XCU1 document is part of the Base Specifications, Issue 6. XCU describes the shell and utilities that are available to application programs on systems conformant to this part of the Single UNIX Specification. Readers are expected to be familiar with the XBD document.
This document is structured as follows:
Chapter 1 explains the status of this document and its relationship to other formal standards, including the ISO C standard and also the XSH document. It also describes the utility limits, grammar conventions, defaults used by the utility descriptions, considerations for utilities in support of large files, and the list of required built-in utilities. The scope, conformance, and definitions sections are pointers to the XBD document; the sections are here to meet ISO/IEC rules regarding required sections. The terminology and portability codes are identical to the section in XBD and repeated here for ease of reference.
Chapter 2 describes the command language-that is, the shell command language interpreter-used in systems conformant to the Single UNIX Specification.
Chapter 3 describes a set of services and utilities that are implemented on systems supporting the Batch Environment option.
Chapter 4 consists of reference pages for all utilities available on systems conforming to the Single UNIX Specification. These are in the form of reference pages and are organized alphabetically.