CAN/CSA-ISO/IEC-9945-2-96

The international community has decided to make this standard available only in the English language version. It has been adopted as a National Standard of Canada on this basis. This National Standard of Canada is equivalent to International Standard ISO/IEC 9945-2:1993 and ANSI/IEEE Std 1003.2-1993. 1.1 Scope This part of ISO/IEC 9945 defines a standard source-code-level interface to command interpretation, or "shell," services and common utility programs for application programs. These services and programs are complementary to those specified by ISO/IEC 9945-1:1990 (IEEE Std 1003.1-1990) {8}, hereinafter referred to as "POSIX.1 {8}." When the User Portability Utilities Option is included, this part of ISO/IEC 9945 has additional scope. The list of utilities and features is extended to provide a common interactive environment for system users and program developers. This part of ISO/IEC 9945 has been designed to be used by both application programmers and system implementors. When the User Portability Utilities Option is included, it is also to be used by system users and program developers. However, it is intended to be a reference document and not a tutorial on the use of the services, the utilities, or the interrelationships between the utilities. The emphasis of this part of ISO/IEC 9945 without the User Portability Utilities Option is on the shell and utility functionality required by application programs (including "shell scripts") and not on the direct interactive use of the shell command language or the utilities by humans. When the User Portability Utilities Option is included, the emphasis is extended to support terminal users in a consistent manner across all conforming systems. There are three constraining factors that limit this user portability scope: (1) The users in this context are limited to the group of individuals who are familiar with the style of interaction characteristic of historically derived systems based on one of the UNIX operating systems. Typical users would include program developers, engineers, or general purpose time-sharing users. (2) The environment to be supported is a multi-user time-sharing system supporting character-oriented display terminals. Alternatively, it is a collection of single-user systems interconnected via local area networks or telephone lines, but with similar user interfaces. This part of ISO/IEC 9945 does not include support that is tailored for bit-mapped or graphics display terminals, although it is expected that such terminals could emulate the character orientation required by this environment. When facilities require cursor addressability from the terminal hardware, this is specifically identified in this part of ISO/IEC 9945. (3) The facilities to be provided are based on the historical models of the following documents: the System V Interface Definition {B37}, the BSD User Manual {B46}, the X/Open Portabitity Guide {B49}, and documentation for the KornShell {B38}. Emphasis is placed on standardizing existing practice for existing users, with changes or additions limited to correcting deficiencies in the following areas: (a) Support for international character sets and other localization requirements, such as date formats, collation sequences, etc. (b) Reconciliation of differences between the historical implementations. (c) Elimination of system or device dependencies. (d) Corrections of features that could reduce system or user security/integrity. Portions of this part of ISO/IEC 9945 comprise optional language bindings to system service interfaces. (See, for example, the C-Language Bindings Option in Annex B.) This part of ISO/IEC 9945 is intended to d