Red Hat Enterprise Linux 3 Reference Guide Red Hat Enterprise Linux 3: Reference Guide Copyright © 2003 by Red Hat, Inc. Red Hat, Inc. 1801 Varsity Drive Raleigh NC 27606-2072 USA Phone: +1 919 754 3700 Phone: 888 733 4281 Fax: +1 919 754 3701 PO Box 13588 Research Triangle Park NC 27709 USA rhel-rg(EN)-3-Print-RHI (2003-07-25T17:13) Copyright © 2003 by Red Hat, Inc. This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, V1.0 or later (the latest version is presently available at http://www.opencontent.org/openpub/). Distribution of substantively modified versions of this document is prohibited without the explicit permission of the copyright holder. Distribution of the work or derivative of the work in any standard (paper) book form for commercial purposes is prohibited unless prior permission is obtained from the copyright holder. Red Hat, Red Hat Network, the Red Hat "Shadow Man" logo, RPM, Maximum RPM, the RPM logo, Linux Library, PowerTools, Linux Undercover, RHmember, RHmember More, Rough Cuts, Rawhide and all Red Hat-based trademarks and logos are trademarks or registered trademarks of Red Hat, Inc. in the United States and other countries. Linux is a registered trademark of Linus Torvalds. Motif and UNIX are registered trademarks of The Open Group. Intel and Pentium are a registered trademarks of Intel Corporation. Itanium and Celeron are trademarks of Intel Corporation. AMD, Opteron, Athlon, Duron, and K6 are registered trademarks of Advanced Micro Devices, Inc. Netscape is a registered trademark of Netscape Communications Corporation in the United States and other countries. Windows is a registered trademark of Microsoft Corporation. SSH and Secure Shell are trademarks of SSH Communications Security, Inc. FireWire is a trademark of Apple Computer Corporation. IBM, AS/400, OS/400, RS/6000, S/390, and zSeries are registered trademarks of International Business Machines Corporation. eServer, iSeries, and pSeries are trademarks of International Business Machines Corporation. All other trademarks and copyrights referred to are the property of their respective owners. The GPG fingerprint of the [email protected] key is: CA 20 86 86 2B D6 9D FC 65 F6 EC C4 21 91 80 CD DB 42 A6 0E Table of Contents Introduction..........................................................................................................................................i 1. Changes To This Manual .......................................................................................................i 2. Finding Appropriate Documentation ....................................................................................ii 2.1. Documentation For First-Time Linux Users..........................................................ii 2.2. For the More Experienced .................................................................................... iv 2.3. Documentation for Linux Gurus............................................................................ v 3. Document Conventions......................................................................................................... v 4. Using the Mouse .................................................................................................................vii 5. Copying and Pasting Text With X......................................................................................viii 6. More to Come ....................................................................................................................viii 6.1. We Need Feedback! ............................................................................................viii 7. Sign Up for Support...........................................................................................................viii I. System Reference..............................................................................................................................i 1. Boot Process, Init, and Shutdown ......................................................................................... 1 1.1. The Boot Process ................................................................................................... 1 1.2. A Detailed Look at the Boot Process..................................................................... 1 1.3. Running Additional Programs at Boot Time ......................................................... 6 1.4. SysV Init Runlevels ............................................................................................... 7 1.5. Shutting Down ....................................................................................................... 8 2. Boot Loaders....................................................................................................................... 11 2.1. Boot Loaders and System Architecture ............................................................... 11 2.2. GRUB................................................................................................................... 11 2.3. Installing GRUB .................................................................................................. 12 2.4. GRUB Terminology............................................................................................. 13 2.5. GRUB Interfaces.................................................................................................. 15 2.6. GRUB Commands ............................................................................................... 16 2.7. GRUB Menu Configuration File.......................................................................... 17 2.8. LILO .................................................................................................................... 19 2.9. The LILO Configuration File............................................................................... 20 2.10. Changing Runlevels at Boot Time ..................................................................... 22 2.11. Additional Resources......................................................................................... 22 3. File System Structure.......................................................................................................... 25 3.1. Why Share a Common Structure?........................................................................ 25 3.2. Overview of File System Hierarchy Standard (FHS) .......................................... 25 3.3. Special File Locations Under Red Hat Enterprise Linux..................................... 29 4. The sysconfig Directory.................................................................................................. 31 4.1. Files in the /etc/sysconfig/ Directory.......................................................... 31 4.2. Directories in the /etc/sysconfig/ Directory................................................ 42 4.3. Additional Resources........................................................................................... 43 5. The proc File System......................................................................................................... 45 5.1. A Virtual File System........................................................................................... 45 5.2. Top-level Files within the proc File System....................................................... 46 5.3. Directories within /proc/................................................................................... 60 5.4. Using the sysctl Command .............................................................................. 76 5.5. Additional Resources........................................................................................... 77 6. Users and Groups................................................................................................................ 79 6.1. User and Group Management Tools .................................................................... 79 6.2. Standard Users ..................................................................................................... 79 6.3. Standard Groups................................................................................................... 81 6.4. User Private Groups ............................................................................................. 83 6.5. Shadow Passwords............................................................................................... 84 6.6. Additional Resources........................................................................................... 84 7. The X Window System ....................................................................................................... 87 7.1. XFree86................................................................................................................ 87 7.2. Desktop Environments and Window Managers................................................... 88 7.3. XFree86 Server Configuration Files .................................................................... 89 7.4. Fonts..................................................................................................................... 95 7.5. Runlevels and XFree86........................................................................................ 98 7.6. Additional Resources........................................................................................... 99 II. Network Services Reference...................................................................................................... 101 8. Network Interfaces...........................................................................................................