The Linux System Administrator's Guide

Version 0.9

Lars Wirzenius

Joanna Oja

Stephen Stafford

Alex Weeks

Table of Contents

About This Book

1. Acknowledgments

2. Revision History

3. Source and pre-formatted versions available

4. Typographical Conventions

1. Introduction

1.1. Linux or GNU/Linux, that is the question.

1.2. Trademarks

2. Overview of a Linux System

2.1. Various parts of an operating system

2.2. Important parts of the kernel

2.3. Major services in a UNIX system

3. Overview of the Directory Tree

3.1. Background

3.2. The root filesystem

3.3. The /etc directory

3.4. The /dev directory

3.5. The /usr filesystem.

3.6. The /var filesystem

3.7. The /proc filesystem

4. Hardware, Devices, and Tools

4.1. Hardware Utilities

4.2. Kernel Modules

5. Using Disks and Other Storage Media

5.1. Two kinds of devices

5.2. Hard disks

5.3. Storage Area Networks - Draft

5.4. Network Attached Storage - Draft

5.5. Floppies

5.6. CD-ROMs

5.7. Tapes

5.8. Formatting

5.9. Partitions

5.10. Filesystems

5.11. Disks without filesystems

5.12. Allocating disk space

6. Memory Management

6.1. What is virtual memory?

6.2. Creating a swap space

6.3. Using a swap space

6.4. Sharing swap spaces with other operating systems

6.5. Allocating swap space

6.6. The buffer cache

7. System Monitoring

7.1. System Resources

7.2. Filesystem Usage

7.3. Monitoring Users

8. Boots And Shutdowns

8.1. An overview of boots and shutdowns

8.2. The boot process in closer look

8.3. More about shutdowns

8.4. Rebooting

8.5. Single user mode

8.6. Emergency boot floppies

9. init

9.1. init comes first

9.2. Configuring init to start getty: the /etc/inittab file

9.3. Run levels

9.4. Special configuration in /etc/inittab

9.5. Booting in single user mode

10. Logging In And Out

10.1. Logins via terminals

10.2. Logins via the network

10.3. What login does

10.4. X and xdm

10.5. Access control

10.6. Shell startup

11. Managing user accounts

11.1. What's an account?

11.2. Creating a user

11.3. Changing user properties

11.4. Removing a user

11.5. Disabling a user temporarily

12. Backups

12.1. On the importance of being backed up

12.2. Selecting the backup medium

12.3. Selecting the backup tool

12.4. Simple backups

12.5. Multilevel backups

12.6. What to back up

12.7. Compressed backups

13. Task Automation --To Be Added

14. Keeping Time

14.1. The concept of localtime

14.2. The hardware and software clocks

14.3. Showing and setting time

14.4. When the clock is wrong

14.5. NTP - Network Time Protocol

14.6. Basic NTP configuration

14.7. NTP Toolkit

14.8. Some known NTP servers

14.9. NTP Links

15. System Logs --To Be Added

16. System Updates --To Be Added

17. The Linux Kernel Source

18. Finding Help

18.1. Newsgroups and Mailing Lists

18.2. IRC

A. GNU Free Documentation License

A.1. PREAMBLE

A.2. APPLICABILITY AND DEFINITIONS

A.3. VERBATIM COPYING

A.4. COPYING IN QUANTITY

A.5. MODIFICATIONS

A.6. COMBINING DOCUMENTS

A.7. COLLECTIONS OF DOCUMENTS

A.8. AGGREGATION WITH INDEPENDENT WORKS

A.9. TRANSLATION

A.10. TERMINATION

A.11. FUTURE REVISIONS OF THIS LICENSE

A.12. ADDENDUM: How to use this License for your documents

Glossary (DRAFT, but not for long hopefully)

Index-Draft

List of Tables

5-1. Comparing Filesystem Features

5-2. Sizes

5-3. My Partitions

9-1. Run level numbers

12-1. Efficient backup scheme using many backup levels

List of Figures

2-1. Some of the more important parts of the Linux kernel

3-1. Parts of a Unix directory tree. Dashed lines indicate partition limits.

5-1. A schematic picture of a hard disk.

5-2. A sample hard disk partitioning.

5-3. Three separate filesystems.

5-4. /home and /usr have been mounted.

10-1. Logins via terminals: the interaction of init, getty, login, and the shell.

12-1. A sample multilevel backup schedule.