Introduction
System Administrator?
•
系統管理員•
不只是IT•
管理別人/大家使用的系統•
http://www.theage.com.au/articles/2002/12/27/1040511172494 .html工作內容
•
裝機設定/更新•
讓機器/系統不要掛•
找問題•
引進並整合新科技•
寫文件•
未雨綢繆 - 防災演練•
資訊安全工作需求
•
能力傾向 (aptitude)•
快速上手複雜的東西•
掌握東西如何運作•
小心行事•
把東西搞爆了可以很快救回來•
溝通技巧•
品德操守參考資料
•
Unix and Linux System Administration Handbook•
Essential System Administration (O'Reilly)•
http://people.cs.nctu.edu.tw/~huanghs/course/s ysadm2011/•
http://www.washington.edu/R870/ (有點舊)•
我們絕對講不完!!UNIX Basics
Linux vs *BSD
•
教派問題•
沒有誰比較好•
發展模式不同o 中央集權
o 各自為政
BSD
•
FreeBSD, OpenBSD, NetBSD, ....•
Developed by Berkeley (B -> Berkeley)•
Kernel + base + boot loader + ....•
Ports/PackagesLinux
•
Kernel•
Distributionso Debian/Ubuntu
o Redhat/CentOS/Fedora
o SUSE
o Slackware
o Gentoo
•
Mostly packagesRoot is God
•
Root can do anythingo Almighty
•
Root can do anythingo Protect it well
o Be careful what you do
o Always logout
o Never login as root
Everything is a file
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Typeso Regular
o Directories
o Links
o Specials (devices)
o Sockets
o Pipes
•
Similar interface for everythingTrees Everywhere
•
Paths starts from / (root)•
Processes start from init (PID 1)File System Structure
•
/ Root•
/home User homes•
/dev Device files•
/bin Basic programs•
/lib* Basic libraries•
/sbin Basic system programs•
/usr Programs/libraries•
/var System data storage•
/proc Process states•
/sys System states•
http://en.wikipedia.org/wiki/Filesystem_Hierarchy_StandardFile Permissions
•
rwx Octal (八進位)•
r - 4 - read•
w - 2 - write•
x - 1 - execute / search rwx = 4+2+1 = 7r-x = 4+1 = 5
File Permissions
rwxrwxrwx 1 wens wens 182 Jun 28 16:13 test.c
Others Group
User
File Permissions
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Owner•
Group•
OthersCheck the first matching type only Check complete path
Path vs Inode
•
Path point in FS to access file•
Inode actual file•
Multiple paths can point to same fileo Hard link
o Share metadata
Inode
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Metadata about a fileo Permissions
o Dates
o Size
o ...
•
Points to disk blocks with contentBasic Commands
Know them well
Command Prompt
Normal user
$ _ Fancy
wens@linux1:/home$ _ Root
# _
Comment (in this document)
##
File/Directory ops
•
cd•
mkdir•
rm•
mv•
ln•
cp•
chown•
chgrp•
chmodman
•
Manual•
Manpages notated as cp(1)•
1 is section## Lookup “cp”
$ man cp
## to be precise $ man 1 cp
## to search for “XXX”
$ man -k XXX
su
•
Switch user$ su root
## Enter root password $ su ta217
## Enter ta217 password
sudo
•
Switch user and do something•
More controlled•
Enter your password $ sudo lsEnter your password run "ls" as root
ps
•
List processes•
man ps for all options $ ps$ ps aux
find
•
find something$ find /home -name wens
## search for file "wens" under /home
$ find /home -exec ls -l {} \;
## search for files in /home and run ls -l {file} for each one
xargs
•
Run a command with a list as arguments$ find | xargs ls –l
# Similar to last find example
grep
•
Look for lines in files containing a pattern•
Regular expressions!$ grep printf *.c
## look for lines in all .c files with printf
df
•
Disk Free•
How much space is free?$ df
$ df /home
du
•
Disk Usage•
How much space is something using?$ du hello.c
## How large is hello.c
$ du ~
## How large are the files in my home?
$ du -s ~
## How large (total) is my home?
vi
•
Vi/Vim•
Text editor$ vim
$ vim hello.c
$ vimtutor
## Tutorial!!
Vim modes
•
Command modecommands (duh)
•
Insert modetype and see
•
Visual mode selectionVim key commands
•
d - delete from here to...•
c - change from here to...•
x - delete 1 (delete key)•
X - delete 1 (backspace)•
y - copy from here to...•
p - paste here•
P - paste before here•
r - replace•
dd - delete line•
yy - copy line•
/XXX - search for XXXVim commands
•
:e xxx - open xxx•
:e! xxx - open xxx without saving•
:w - save•
:w xxx - save as xxx•
:q - quit•
:q! - quit without saving Combine!•
:wq - save and quit回家練習
Vimtutor
工作站上熟悉指令
(chown, chgrp, su, sudo 除外)
作業
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