Red Hat Enterprise Linux 4 Reference Guide Red Hat Enterprise Linux 4: Reference Guide Copyright © 2005 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)-4-Print-RHI (2004-09-30T17:13) Copyright © 2005 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 and the Red Hat "Shadow Man" logo are registered trademarks of Red Hat, Inc. in the United States and other countries. All other trademarks referenced herein 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. Architecture-specific Information ......................................................................................... ii 3. Finding Appropriate Documentation .................................................................................... ii 3.1. Documentation For First-Time Linux Users.......................................................... ii 3.2. For the More Experienced .................................................................................... iv 3.3. Documentation for Linux Gurus........................................................................... iv 4. Document Conventions ........................................................................................................ iv 5. Activate Your Subscription ................................................................................................. vii 5.1. Provide a Red Hat Login...................................................................................... vii 5.2. Provide Your Subscription Number ....................................................................viii 5.3. Connect Your System.......................................................................................... viii 6. Using the Mouse ................................................................................................................ viii 7. Copying and Pasting Text With X...................................................................................... viii 8. More to Come .................................................................................................................... viii 8.1. We Need Feedback! .............................................................................................. ix 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 ............................................................................................... 6 1.5. Shutting Down ....................................................................................................... 8 2. The GRUB Boot Loader ....................................................................................................... 9 2.1. Boot Loaders and System Architecture ................................................................. 9 2.2. GRUB..................................................................................................................... 9 2.3. Installing GRUB .................................................................................................. 10 2.4. GRUB Terminology ............................................................................................. 11 2.5. GRUB Interfaces .................................................................................................. 13 2.6. GRUB Commands ............................................................................................... 14 2.7. GRUB Menu Configuration File.......................................................................... 15 2.8. Changing Runlevels at Boot Time ....................................................................... 17 2.9. Additional Resources ........................................................................................... 17 3. File System Structure.......................................................................................................... 19 3.1. Why Share a Common Structure?........................................................................ 19 3.2. Overview of File System Hierarchy Standard (FHS) .......................................... 19 3.3. Special File Locations Under Red Hat Enterprise Linux..................................... 24 4. The sysconfig Directory.................................................................................................. 27 4.1. Files in the /etc/sysconfig/ Directory .......................................................... 27 4.2. Directories in the /etc/sysconfig/ Directory ................................................ 40 4.3. Additional Resources ........................................................................................... 40 5. The proc File System......................................................................................................... 41 5.1. A Virtual File System........................................................................................... 41 5.2. Top-level Files within the proc File System ....................................................... 42 5.3. Directories within /proc/................................................................................... 58 5.4. Using the sysctl Command .............................................................................. 75 5.5. Additional Resources ........................................................................................... 76 6. Users and Groups................................................................................................................ 77 6.1. User and Group Management Tools .................................................................... 77 6.2. Standard Users ..................................................................................................... 77 6.3. Standard Groups................................................................................................... 79 6.4. User Private Groups ............................................................................................. 81 6.5. Shadow Passwords............................................................................................... 82 6.6. Additional Resources ........................................................................................... 83 7. The X Window System ....................................................................................................... 85 7.1. The X11R6.8 Release .......................................................................................... 85 7.2. Desktop Environments and Window Managers ................................................... 86 7.3. X Server Configuration Files ............................................................................... 87 7.4. Fonts..................................................................................................................... 93 7.5. Runlevels and X ................................................................................................... 96 7.6. Additional Resources ........................................................................................... 97 II. Network Services Reference........................................................................................................ 99 8. Network Interfaces ............................................................................................................ 101 8.1. Network Configuration Files.............................................................................. 101 8.2. Interface Configuration Files ............................................................................. 102 8.3. Interface Control Scripts .................................................................................... 108 8.4. Network Function Files...................................................................................... 110 8.5. Additional Resources ......................................................................................... 110 9. Network File System (NFS).............................................................................................