About This Book

Command and Shell User's Guide introduces users to the basic use of commands and shells in the Digital UNIX® operating system. This book also documents how to communicate with other network users.

This preface covers the following topics:

Audience
Scope
Organization
Related Documents
Conventions

Audience

This book is written for those who do not have extensive knowledge of UNIX compatible operating systems. This book explains important concepts, provides tutorials, and is organized according to task.

Scope

This book introduces you to the use of commands and shells. After reading this book, you should be able to:

Gain access to your system and issue commands
Understand file and directory concepts
Manage files and directories
Control access to your files and directories
Manage processes
Understand and manage your shell environment
Use the vi and ed text editors
Use network applications to communicate with network users and access remote systems and processes

Organization

This book is organized into 13 chapters and 6 appendices:

Chapter 1: Shows how to log in and out of your system, enter commands, set your password, and obtain online help.

Chapter 2: Provides an overview of the file system, consisting of the files and directories that are used to store text, programs, and other data. This chapter also introduces you to the vi text editor, a program that allows you to create and modify files.

Chapter 3: Shows how to manage files. You will learn how to list, display, copy, move, link, and remove them.

Chapter 4: Explains how to manage directories. You will learn how to create, change, display, copy, rename, and remove them.

Chapter 5: Shows how to control access to your files and directories by setting appropriate permissions. It also describes standard password and group security issues as well as provides an overview of additional security considerations.

Chapter 6: Describes how the operating system creates and keeps track of processes. This chapter explains how to redirect process input, output, and error information, run processes simultaneously, display process information, and cancel processes.

Chapter 7: Introduces features common to the three shells available with the operating system: the Bourne, C, and Korn shells. You learn how to change your shell, use command entry aids, understand some features of your shell environment (login scripts, environment and shell variables), set and clear variables, write logout scripts, and write and run basic shell procedures.

Chapter 8: Provides detailed reference information about the C, Bourne, and Korn shells, comparing their features. It details the commands and environment variables of each program and shows how to set up your login script.

Chapter 9: Shows how to access the System V habitat, a subset of commands, subroutines, and system calls that conforms to the System V Interface Definition (SVID).

Chapter 10: Provides information on how to get information about other users and remote hosts on the network.

Chapter 11: Provides information about how to send a message to another user.

Chapter 12: Provides information about how to copy files to or between remote hosts.

Chapter 13: Provides information about how to log in to or execute commands at a remote host.

Chapter 14: Provides information about the UNIX-to-UNIX Copy Program (UUCP) for performing communication tasks concurrently on both a local and remote host.

The appendixes in this book provide the following information:

Appendix A: Teaches you how to use the basic features of the vi text editor.

Appendix B: Teaches you how to use the ed text editor. Detailed information about ed is provided because all systems have this editor, and ed can be used in critical system management situations when no other editor can be used.

Appendix C: Describes the internationalization features that allow users to process data and interact with the system in a manner appropriate to their native language, customs, and geographic region.

Appendix D: Provides a list of variables that can be used in the .mailrc file to customize a mailx session.

Appendix E: Provides a list of escape commands that can be used to perform certain tasks from within a mailx session.

Appendix F: Provides a list of commands that can be used to send, read, delete, or save messages using mailx.

Reader's Comments

Digital welcomes any comments and suggestions you have on this and other Digital UNIX manuals.

You can send your comments in the following ways:

Fax: 603-881-0120 Attn: UEG Publications, ZK03-3/Y32
Internet electronic mail: readers_comment@zk3.dec.com
A Reader's Comment form is located on your system in the following location:
```
/usr/doc/readers_comment.txt
```
Mail:
Digital Equipment Corporation
UEG Publications Manager
ZK03-3/Y32
110 Spit Brook Road
Nashua, NH 03062-9987
A Reader's Comment form is located in the back of each printed manual. The form is postage paid if you mail it in the United States.

Please include the following information along with your comments:

The full title of the book and the order number. (The order number is printed on the title page of this book and on its back cover.)
The section numbers and page numbers of the information on which you are commenting.
The version of Digital UNIX that you are using.
If known, the type of processor that is running the Digital UNIX software.

The Digital UNIX Publications group cannot respond to system problems or technical support inquiries. Please address technical questions to your local system vendor or to the appropriate Digital technical support office. Information provided with the software media explains how to send problem reports to Digital.

Conventions

The following conventions are used in this book:

%
$ A percent sign represents the C shell system prompt. A dollar sign represents the system prompt for the Bourne and Korn shells.

# A number sign represents the superuser prompt.

% cat Boldface type in interactive examples indicates typed user input.

file Italic (slanted) type indicates variable values, placeholders, and function argument names.

[ | ]
{ | } In syntax definitions, brackets indicate items that are optional and braces indicate items that are required. Vertical bars separating items inside brackets or braces indicate that you choose one item from among those listed.

. . . In syntax definitions, a horizontal ellipsis indicates that the preceding item can be repeated one or more times.

cat(1) A cross-reference to a reference page includes the appropriate section number in parentheses. For example, cat(1) indicates that you can find information on the cat command in Section 1 of the reference pages.

Ctrl/x This symbol indicates that you hold down the first named key while pressing the key or mouse button that follows the slash. In examples, this key combination is enclosed in a box (for example, [Ctrl/C]).

Audience	Icon	Color Code
General users	G	Blue
System and network administrators	S	Red
Programmers	P	Purple
Device driver writers	D	Orange
Reference page users	R	Green