文件名称：Linux System Administrator Guide Version0.9
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更新时间：2011-03-31 03:41:53
Administrator Linux
Linux System Administrator Guide Version0.9
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
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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
5.8. Formatting.......................................................................................................................................31
5.9. Partitions.........................................................................................................................................32
5.9.1. The MBR, boot sectors and partition table............................................................................33
5.9.2. Extended and logical partitions.............................................................................................33
5.9.3. Partition types........................................................................................................................34
5.9.4. Partitioning a hard disk..........................................................................................................35
5.9.5. Device files and partitions.....................................................................................................36
5.10. Filesystems....................................................................................................................................36
5.10.1. What are filesystems?..........................................................................................................36
5.10.2. Filesystems galore...............................................................................................................37
5.10.3. Which filesystem should be used?......................................................................................39
5.10.4. Creating a filesystem...........................................................................................................39
5.10.5. Filesystem block size...........................................................................................................40
5.10.6. Filesystem comparison........................................................................................................41
5.10.7. Mounting and unmounting..................................................................................................42
5.10.8. Filesystem Security.............................................................................................................45
5.10.9. Checking filesystem integrity with fsck..............................................................................45
5.10.10. Checking for disk errors with badblocks...........................................................................46
5.10.11. Fighting fragmentation?....................................................................................................46
5.10.12. Other tools for all filesystems...........................................................................................47
5.10.13. Other tools for the ext2/ext3 filesystem............................................................................47
5.11. Disks without filesystems.............................................................................................................48
5.12. Allocating disk space....................................................................................................................49
5.12.1. Partitioning schemes............................................................................................................49
5.12.2. Logical Volume Manager (LVM).......................................................................................50
5.12.3. Space requirements..............................................................................................................50
5.12.4. Examples of hard disk allocation........................................................................................50
5.12.5. Adding more disk space for Linux......................................................................................51
5.12.6. Tips for saving disk space...................................................................................................51
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Chapter 6. Memory Management...................................................................................................................52
6.1. What is virtual memory?.................................................................................................................52
6.2. Creating a swap space.....................................................................................................................52
6.3. Using a swap space.........................................................................................................................53
6.4. Sharing swap spaces with other operating systems........................................................................54
6.5. Allocating swap space.....................................................................................................................55
6.6. The buffer cache.............................................................................................................................56
Chapter 7. System Monitoring.........................................................................................................................58
7.1. System Resources...........................................................................................................................58
7.1.1. The top command..................................................................................................................58
7.1.2. The iostat command..............................................................................................................59
7.1.3. The ps command...................................................................................................................60
7.1.4. The vmstat command............................................................................................................61
7.1.5. The lsof command.................................................................................................................61
7.1.6. Finding More Utilities...........................................................................................................62
7.2. Filesystem Usage............................................................................................................................62
7.2.1. The df command....................................................................................................................62
7.2.2. The du command...................................................................................................................62
7.2.3. Quotas....................................................................................................................................63
7.3. Monitoring Users............................................................................................................................63
7.3.1. The who command................................................................................................................63
7.3.2. The ps command -again!......................................................................................................64
7.3.3. The w command....................................................................................................................64
7.3.4. The skill command................................................................................................................64
7.3.5. nice and renice.......................................................................................................................64
Chapter 8. Boots And Shutdowns....................................................................................................................65
8.1. An overview of boots and shutdowns.............................................................................................65
8.2. The boot process in closer look......................................................................................................65
8.2.1. A Word About Bootloaders...................................................................................................67
8.3. More about shutdowns....................................................................................................................67
8.4. Rebooting........................................................................................................................................68
8.5. Single user mode.............................................................................................................................69
8.6. Emergency boot floppies................................................................................................................69
Chapter 9. init....................................................................................................................................................70
9.1. init comes first................................................................................................................................70
9.2. Configuring init to start getty: the/etc/inittab file..........................................................................70
9.3. Run levels.......................................................................................................................................71
9.4. Special configuration in/etc/inittab................................................................................................73
9.5. Booting in single user mode...........................................................................................................73
Chapter 10. Logging In And Out.....................................................................................................................75
10.1. Logins via terminals......................................................................................................................75
10.2. Logins via the network..................................................................................................................76
10.3. What login does............................................................................................................................77
10.4. X and xdm.....................................................................................................................................78
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Chapter 10. Logging In And Out
10.5. Access control...............................................................................................................................78
10.6. Shell startup..................................................................................................................................78
Chapter 11. Managing user accounts..............................................................................................................79
11.1. What's an account?........................................................................................................................79
11.2. Creating a user..............................................................................................................................79
11.2.1./etc/passwd and other informative files...............................................................................79
11.2.2. Picking numeric user and group ids....................................................................................80
11.2.3. Initial environment: /etc/skel...............................................................................................80
11.2.4. Creating a user by hand.......................................................................................................80
11.3. Changing user properties..............................................................................................................81
11.4. Removing a user...........................................................................................................................81
11.5. Disabling a user temporarily.........................................................................................................82
Chapter 12. Backups.........................................................................................................................................83
12.1. On the importance of being backed up.........................................................................................83
12.2. Selecting the backup medium.......................................................................................................83
12.3. Selecting the backup tool..............................................................................................................84
12.4. Simple backups.............................................................................................................................85
12.4.1. Making backups with tar.....................................................................................................85
12.4.2. Restoring files with tar........................................................................................................86
12.5. Multilevel backups........................................................................................................................87
12.6. What to back up............................................................................................................................88
12.7. Compressed backups.....................................................................................................................89
Chapter 13. Task Automation --To Be Added.............................................................................................90
Chapter 14. Keeping Time...............................................................................................................................91
14.1. The concept of localtime...............................................................................................................91
14.2. The hardware and software clocks................................................................................................92
14.3. Showing and setting time..............................................................................................................92
14.4. When the clock is wrong...............................................................................................................93
14.5. NTP - Network Time Protocol.....................................................................................................93
14.6. Basic NTP configuration...............................................................................................................94
14.7. NTP Toolkit..................................................................................................................................95
14.8. Some known NTP servers.............................................................................................................97
14.9. NTP Links.....................................................................................................................................97
Chapter 15. System Logs --To Be Added......................................................................................................98
Chapter 16. System Updates --To Be Added................................................................................................99
Chapter 17. The Linux Kernel Source..........................................................................................................100
Chapter 18. Finding Help...............................................................................................................................101
18.1. Newsgroups and Mailing Lists...................................................................................................101
18.1.1. Finding The Right Forum..................................................................................................101
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Chapter 18. Finding Help
18.1.2. Before You Post................................................................................................................101
18.1.3. Writing Your Post.............................................................................................................101
18.1.4. Formatting Your Post........................................................................................................102
18.1.5. Follow Up..........................................................................................................................102
18.1.6. More Information..............................................................................................................102
18.2. IRC..............................................................................................................................................102
18.2.1. Colours..............................................................................................................................103
18.2.2. Be Polite............................................................................................................................103
18.2.3. Type Properly, in English..................................................................................................103
18.2.4. Port scanning.....................................................................................................................103
18.2.5. Keep it in the Channel.......................................................................................................103
18.2.6. Stay On Topic....................................................................................................................104
18.2.7. CTCPs...............................................................................................................................104
18.2.8. Hacking, Cracking, Phreaking, Warezing.........................................................................104
18.2.9. Round Up..........................................................................................................................104
18.2.10. Further Reading...............................................................................................................104
Appendix A. GNU Free Documentation License.........................................................................................105
A.1. PREAMBLE................................................................................................................................105
A.2. APPLICABILITY AND DEFINITIONS....................................................................................105
A.3. VERBATIM COPYING..............................................................................................................106
A.4. COPYING IN QUANTITY.........................................................................................................106
A.5. MODIFICATIONS......................................................................................................................107
A.6. COMBINING DOCUMENTS.....................................................................................................108
A.7. COLLECTIONS OF DOCUMENTS..........................................................................................109
A.8. AGGREGATION WITH INDEPENDENT WORKS.................................................................109
A.9. TRANSLATION..........................................................................................................................109
A.10. TERMINATION........................................................................................................................109
A.11. FUTURE REVISIONS OF THIS LICENSE.............................................................................110
A.12. ADDENDUM: How to use this License for your documents...................................................110
Glossary (DRAFT, but not for long hopefully)............................................................................................111
Index-Draft..........................................................................................................................................115
A....................................................................................................................................................115
B....................................................................................................................................................115
C....................................................................................................................................................115
D....................................................................................................................................................116
E.....................................................................................................................................................117
F.....................................................................................................................................................117
G....................................................................................................................................................120
H....................................................................................................................................................120
I......................................................................................................................................................120
K....................................................................................................................................................120
L.....................................................................................................................................................121
M...................................................................................................................................................121
N....................................................................................................................................................121
O....................................................................................................................................................121
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Glossary (DRAFT, but not for long hopefully)
P.....................................................................................................................................................121
R....................................................................................................................................................122
S.....................................................................................................................................................122
T.....................................................................................................................................................122
V....................................................................................................................................................122
W...................................................................................................................................................122