The Linux System Administrator's Guide Version 0.9 Lars Wirzenius <Email address removed by request> Joanna Oja <Current email address unknown> Stephen Stafford <[email protected]> Alex Weeks <[email protected]> An introduction to system administration of a Linux system for novices. Copyright 1993−−1998 Lars Wirzenius. Copyright 1998−−2001 Joanna Oja. Copyright 2001−−2003 Stephen Stafford. Copyright 2003−−2004 Stephen Stafford & Alex Weeks. Copyright 2004−−Present Alex Weeks. Trademarks are owned by their owners. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front−Cover Texts, and no Back−Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". The Linux System Administrator's Guide Table of Contents About This Book.................................................................................................................................................1 1. Acknowledgments................................................................................................................................1 1.1. Joanna's acknowledgments.........................................................................................................1 1.2. Stephen's acknowledgments.......................................................................................................1 1.3. Alex's Acknowledgments...........................................................................................................2 2. Revision History..................................................................................................................................2 3. Source and pre−formatted versions available......................................................................................2 4. Typographical Conventions.................................................................................................................3 Chapter 1. Introduction......................................................................................................................................4 1.1. Linux or GNU/Linux, that is the question........................................................................................5 1.2. Trademarks.......................................................................................................................................5 Chapter 2. Overview of a Linux System...........................................................................................................7 2.1. Various parts of an operating system................................................................................................7 2.2. Important parts of the kernel.............................................................................................................7 2.3. Major services in a UNIX system.....................................................................................................8 2.3.1. init............................................................................................................................................9 2.3.2. Logins from terminals.............................................................................................................9 2.3.3. Syslog......................................................................................................................................9 2.3.4. Periodic command execution: cron and at............................................................................10 2.3.5. Graphical user interface.........................................................................................................10 2.3.6. Networking............................................................................................................................10 2.3.7. Network logins......................................................................................................................11 2.3.8. Network file systems.............................................................................................................11 2.3.9. Mail.......................................................................................................................................11 2.3.10. Printing................................................................................................................................12 2.3.11. The filesystem layout..........................................................................................................12 Chapter 3. Overview of the Directory Tree....................................................................................................13 3.1. Background.....................................................................................................................................13 3.2. The root filesystem.........................................................................................................................14 3.3. The /etc directory............................................................................................................................15 3.4. The /dev directory...........................................................................................................................17 3.5. The /usr filesystem..........................................................................................................................19 3.6. The /var filesystem..........................................................................................................................19 3.7. The /proc filesystem........................................................................................................................20 Chapter 4. Hardware, Devices, and Tools......................................................................................................22 4.1. Hardware Utilities...........................................................................................................................22 4.1.1. The MAKEDEV Script.........................................................................................................22 4.1.2. The mknod command............................................................................................................22 4.1.3. The lspci command...............................................................................................................23 4.1.4. The lsdev command...............................................................................................................23 4.1.5. The lsusb command...............................................................................................................23 4.1.6. The lsraid command..............................................................................................................23 4.1.7. The hdparm command...........................................................................................................23 4.1.8. More Hardware Resources....................................................................................................23 i The Linux System Administrator's Guide Table of Contents Chapter 4. Hardware, Devices, and Tools 4.2. Kernel Modules...............................................................................................................................23 4.2.1. lsmod.....................................................................................................................................24 4.2.2. insmod...................................................................................................................................24 4.2.3. depmod..................................................................................................................................24 4.2.4. rmmod...................................................................................................................................24 4.2.5. modprobe...............................................................................................................................24 Chapter 5. Using Disks and Other Storage Media.........................................................................................25 5.1. Two kinds of devices......................................................................................................................25 5.2. Hard disks.......................................................................................................................................26 5.3. Storage Area Networks − Draft......................................................................................................28 5.4. Network Attached Storage − Draft.................................................................................................28 5.4.1. NFS........................................................................................................................................29 5.4.2. CIFS.......................................................................................................................................29 5.5. Floppies...........................................................................................................................................29 5.6. CD−ROMs......................................................................................................................................30 5.7. Tapes...............................................................................................................................................31