Anyone who has accessed either the DOS prompt of a DOS or Windows system, or the shell capabilities of Macintosh OS X has, in fact, already worked at the command-line level. Although graphical interfaces have been displacing command-line interfaces for programming environments, we are among those who still find that the command-line interface introduces less confusion and reveals more details when one is learning about a new architecture. In order to gain the most benefit from this book, you need to have basic familiarity with Hewlett-Packard's Unix (HP-UX) or a Linux command-line environment. In this appendix, we provide a general overview of these command-line programming environments. HP-UX and Linux systems support multiple simultaneous users who log in and have a home directory for file storage that is unique for each user. The manager of the system assigns usernames and initial passwords. These systems, unlike the traditional versions of DOS, make distinctions between upper- and lowercase characters in almost all contexts. Lowercase characters usually predominate. |