The Linux System Administrator's Guide

1 The Linux System Administrator's GuideVersion Wirzenius<Email address removed by request>Joanna Oja<Current email address unknown>Stephen introduction to System administration of a Linux System for 1993 1998 Lars 1998 2001 Joanna 2001 2003 Stephen 2003 2004 Stephen Stafford & Alex 2004 Present Alex are owned by their is granted to copy, distribute and/or modify this document under the terms of the GNU FreeDocumentation License, Version or any later version published by the Free Software Foundation; with noInvariant Sections, no Front Cover Texts, and no Back Cover Texts.

2 A copy of the license is included in thesection entitled "GNU Free Documentation License".Table of ContentsAbout This Joanna's Stephen's Alex's Revision Source and pre formatted versions Typographical 1. Linux or GNU/ Linux , that is the 2. Overview of a Linux Various parts of an operating Important parts of the Major services in a UNIX Logins from Periodic command execution: cron and Graphical user Network Network file The filesystem 3. Overview of the Directory The root The/etc The/dev The/usr The/var The/proc 4.

3 Hardware, Devices, and Hardware The MAKEDEV The mknod The lspci The lsdev The lsusb The lsraid The hdparm More Hardware Linux System Administrator's GuideiTable of ContentsChapter 4. Hardware, Devices, and Kernel 5. Using Disks and Other Storage Two kinds of Hard Storage Area Networks Network Attached Storage CD The MBR, boot sectors and partition Extended and logical Partition Partitioning a hard Device files and What are filesystems?.. Filesystems Which filesystem should be used?

4 Creating a Filesystem block Filesystem Mounting and Filesystem Checking filesystem integrity with Checking for disk errors with Fighting fragmentation?.. Other tools for all Other tools for the ext2/ext3 Disks without Allocating disk Partitioning Logical Volume Manager (LVM).. Space Examples of hard disk Adding more disk space for Tips for saving disk Linux System Administrator's GuideiiTable of ContentsChapter 6. Memory What is virtual memory?.. Creating a swap Using a swap Sharing swap spaces with other operating Allocating swap The buffer 7.

5 System System The top The iostat The ps The vmstat The lsof Finding More Filesystem The df The du Monitoring The who The ps command again!.. The w The skill nice and 8. Boots And An overview of boots and The boot process in closer A Word About More about Single user Emergency boot 9. init comes Configuring init to start getty: the/etc/inittab Run Special configuration in/ Booting in single user 10. Logging In And Logins via Logins via the What login X and Linux System Administrator's GuideiiiTable of ContentsChapter 10.

6 Logging In And Access Shell 11. Managing user What's an account?.. Creating a and other informative Picking numeric user and group Initial environment:/ Creating a user by Changing user Removing a Disabling a user 12. On the importance of being backed Selecting the backup Selecting the backup Simple Making backups with Restoring files with Multilevel What to back Compressed 13. Task Automation To Be 14. Keeping The concept of The hardware and software Showing and setting When the clock is NTP Network Time Basic NTP NTP Some known NTP NTP 15.

7 System Logs To Be 16. System Updates To Be 17. The Linux Kernel 18. Finding Newsgroups and Mailing Finding The Right Linux System Administrator's GuideivTable of ContentsChapter 18. Finding Before You Writing Your Formatting Your Follow More Be Type Properly, in Port Keep it in the Stay On Hacking, Cracking, Phreaking, Round Further A. GNU Free Documentation APPLICABILITY AND VERBATIM COPYING IN COMBINING COLLECTIONS OF AGGREGATION WITH INDEPENDENT FUTURE REVISIONS OF THIS ADDENDUM: How to use this License for your (DRAFT, but not for long hopefully).

8 111 Index Linux System Administrator's GuidevTable of ContentsGlossary (DRAFT, but not for long hopefully) Linux System Administrator's GuideviAbout This Book"Only two things are infinite, the universe and human stupidity, and I'm not sure about theformer." Albert Einstein1. Joanna's acknowledgmentsMany people have helped me with this book, directly or indirectly. I would like to especially thank MattWelsh for inspiration and LDP leadership, Andy Oram for getting me to work again with much valuedfeedback, Olaf Kirch for showing me that it can be done, and Adam Richter at Yggdrasil and others forshowing me that other people can find it interesting as Tweedie, H.

9 Peter Anvin, Remy Card, Theodore Ts'o, and Stephen Tweedie have let me borrow theirwork (and thus make the book look thicker and much more impressive): a comparison between the xia andext2 filesystems, the device list and a description of the ext2 filesystem. These aren't part of the book anymore. I am most grateful for this, and very apologetic for the earlier versions that sometimes lacked addition, I would like to thank Mark Komarinski for sending his material in 1993 and the many systemadministration columns in Linux Journal. They are quite informative and useful comments have been sent by a large number of people.

10 My miniature black hole of an archivedoesn't let me find all their names, but some of them are, in alphabetical order: Paul Caprioli, Ales Cepek,Marie France Declerfayt, Dave Dobson, Olaf Flebbe, Helmut Geyer, Larry Greenfield and his father, StephenHarris, Jyrki Havia, Jim Haynes, York Lam, Timothy Andrew Lister, Jim Lynch, Michael J. Micek, JacobNavia, Dan Poirier, Daniel Quinlan, Jouni K Sepp nen, Philippe Steindl, Stotte. My apologies to anyoneI have Stephen's acknowledgmentsI would like to thank Lars and Joanna for their hard work on the a Guide like this one there are likely to be at least some minor inaccuracies.