UNIX System Administration Handbook

1325 Pages·2012·14.24 MB·English

by  Nemeth Evi

®
UNIX System Administration
Handbook

Third Edition

Evi Nemeth
Garth Snyder
Scott Seebass
Trent R. Hein

with
Adam Boggs, Rob Braun, Dan Crawl, Ned McClain, Lynda McGinley, and Todd
Miller
Prentice Hall PTR
Upper Saddle River, NJ 07458
www.phptr.com
Editorial/production supervisor: Patti Guerrieri
Acquisitions editor: Mary Franz
Marketing manager: Bryan Gambrel
Manufacturing manager: Maura Zaldivar
Editorial assistant: Noreen Regina
Cover design director: Jerry Votta
Cover designers: Garth Snyder and Tyler Curtain

© 2001 by Prentice Hall PTR
Prentice-Hall, Inc.
Upper Saddle River, NJ 07458
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Printed in the United States of America
10 9 8 7 6 5 4 3 2 1
ISBN 0-13-020601-6
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We dedicate this edition of UNIX System Administration Handbook to the
memory of three giants in the UNIX and Internet worlds: John Lions, Jon Postel,
and Rich Stevens.
John Lions, a professor at the University of New South Wales, wrote a
wonderful commentary on the UNIX source code in the mid-1970s. It explained
the 10,000 lines of code that made up UNIX in those days; John’s book was used
in operating systems classes around the world. A copyright dispute forced the
book out of print, but it circulated among students for years in the form of
photocopies of photocopies. Ours is hardly readable. John died in December,
1998.

Jon Postel was the editor of the RFC series (as well as the author of many
RFCs), the benevolent dictator of Internet names and numbers, and the technical
conscience of the Internet. For years he led the way as the Internet was
transformed from a playground of geeks and university students to perhaps the
most significant social and economic force since the industrial revolution. Jon
died in October, 1998. (www.postel.org)

Rich Stevens is well known in academia for his wonderful books on networking
and UNIX programming. Students love these books because Rich’s examples
always show exactly how to do something or just how to find out what the
network protocols are really doing. Rich’s generous contributions to the Internet
community often took the form of answers to TCP questions raised on network-
related mailing lists. It’s hard to imagine a more accessible or more authoritative
source; the second volume of Rich’s TCP/IP Illustrated series was effectively
the definition of TCP. Rich died in September, 1999. (www.kohala.com)
Table of Contents

FOREWORD
FOREWORD TO THE SECOND EDITION
FOREWORD TO THE FIRST EDITION
PREFACE
ACKNOWLEDGMENTS
BASIC ADMINISTRATION
CHAPTER 1 WHERE TO START
Suggested background
The sordid history of UNIX
Example UNIX systems
Notation and typographical conventions
System-specific information
How to use your manuals
Organization of the man pages
man: read manual pages
Essential tasks of the system administrator
Adding and removing users
Adding and removing hardware
Performing backups
Installing new software
Monitoring the system
Troubleshooting
Maintaining local documentation
Auditing security
Helping users
How to find files on the Internet
System administration under duress
System Administration Personality Syndrome
Recommended reading
CHAPTER 2 BOOTING AND SHUTTING DOWN
Bootstrapping
Automatic and manual booting
Steps in the boot process
Kernel initialization
Hardware configuration
System processes
Operator intervention (manual boot only)
Execution of startup scripts
Multiuser operation
Booting PCs
How a PC is different from proprietary hardware
The PC boot process
LILO: the Linux boot loader
Configuring LILO
The FreeBSD boot loader
Multibooting on PCs
Multibooting gotchas
LILO multiboot configuration
FreeBSD multiboot configuration
Booting in single-user mode
Solaris single-user mode
HP-UX single-user mode
Linux single-user mode
FreeBSD single-user mode
Startup scripts
SystemV-style startup scripts
Solaris startup scripts
HP-UX startup scripts
Red Hat startup scripts
FreeBSD startup scripts
Rebooting and shutting down
Turning off the power
shutdown: the genteel way to halt the system
halt: a simpler way to shut down
reboot: quick and dirty restart
Sending init a TERM signal
telinit: change init’s run level
Killing init
CHAPTER 3 ROOTLY POWERS
Ownership of files and processes
The superuser
Choosing a root password
Becoming root
su: substitute user identity
sudo: a limited su
Other pseudo-users
daemon: owner of unprivileged system software
bin: owner of system commands
sys: owner of the kernel and memory images
nobody: the generic NFS user
CHAPTER 4 CONTROLLING PROCESSES
Components of a process
PID: process ID number
PPID: parent PID
UID and EUID: real and effective user ID
GID and EGID: real and effective group ID
Niceness
Control terminal
The life cycle of a process
Signals
kill: send signals
Process states
nice and renice: influence scheduling priority
ps: monitor processes
top: monitor processes even better
Runaway processes
CHAPTER 5 THE FILESYSTEM
Pathnames
Mounting and unmounting filesystems
The organization of the file tree
File types
Regular files
Directories
Character and block device files
UNIX domain sockets
Named pipes
Symbolic links
File attributes
The setuid and setgid bits
The sticky bit
The permission bits