RH033学习笔记

共12个Unit   ===============================================================================
RH033-01
RH4 ES 的安装过程
1,建立了/boot,/和/swap三个分区
2,语言选择都是en
3,软件包默认
===============================================================================
RH033-02
RH033共有3个Section
Objecttives of RH033 FIle and directory operations
Understanding users and groups
Standard I/O and pipes
String processing
Managing processes
bash shell operations
The graphical environments in Red Hat Enterprise Linux
Print and Mial
Basic networking tools
The vi editor
System tools
===============================================================================
Unit 1 - Overview
1,UNIX history
2,UNIX princliples
3,GNU Project/FSF
4,GPL- GNU General Pbulic License
5,Linux Origins
6,Why Linux
7,Red Hat Enterprise Linux
8,Recommended Hardware Specifications
9,Local Logins
10,Virtual Consoles
11,The Xorg GUI Framework
12,Xorg Graphical Environments
13,Starting Xorg
14,Changing Your Password 1,UNIX history
AT&T注册了UNIX商标
2,UNIX princliples
 Everything is a file (including hardware)
 Configuration data stored in text
 Small,single-purpose programs
 Avoid captive user interfaces
 Ability to chain programs together to perform comples tasks 串联多个小程序执行复杂任务
3,GNU Project/FSF
 Goal:Create "free" UNIX clone
 started in 1984
 4中自由:使用,学习,散布,改善
4,GPL- GNU General Pbulic License
  Often called "copyleft"
5,Linux Origins
  linus Torvalds in 1991
6,Why Linux
  a UNIX-like OS
  Multi-user and multi-tasking
  Wide hardware support
  Fully supported
7,Red Hat Enterprise Linux
A distribution of Linux
  Custom version of a recent Linux kernel
  Utilities and applicatios
8,Recommended Hardware Specifications
P2 with 256MB RAM
9,Local Logins
  Text-mode 区分管理员和普通用户的提示符不同
  Graphical login
10,Virtual Consoles
  Multiple non-GUI logins
  CTRL+ALT+F1--F6
  tty指令可以判断目前在哪个虚拟控制台
  X在CTRL+ALT+F7里面
11,The Xorg GUI Framework
  clinet/server architecture
  RHEL4:ssh protocol
12,Xorg Graphical Environments
GNOME = The default desktop
KDE
13Starting Xorg
startx
14,Changing Your Password
Password change
passwd指令可以修改自己密码
建议用ACSII code做密码
只有root可能修改他人密码
===============================================================================
Unit 2 - Running Commands and Getting Help
1,Running Commands
2,Some Simple Commands
3,Getting Help
4,The whatis Command
5,The --help Option
6,Reading Usage Summaries
7,The man Command
8,Navigating man Pages
9,The info Command
10,Navigating info Pages
11,Extended Documentation
12,Red Hat Documentation 1,Running Commands
一条指令的3个组成部分,每个部分之间用空格隔开
 command [options] [arguments]
 指令 选项 参数
[options]修改指令功能
如果是整个单词,前面接--,单个字母用- 多个单个字母可以连写如: -a -l写成--al
[arguments]文件名或其它信息
举例:passwd -S user1 查看user1的密码信息
useradd user
passwd --status user2 相同 -S
2,Some Simple Commands
date -s 22:02
date +%T
date +%T%D
cal 6 2008
3,Getting Help
Don't try to memorize everything
 whatis
 <command> --help
 man and info
 /usr/share/doc
 Red Hat documentiation
4,The whatis Command
 Display short description
5,The --help Option
 Displays usage summary and argument list
 used by most but not all,command
6,Reading Usage Summaries
 Arguments in "[]" are optional
 Arguments in "<>" are variables
 x|y|z means "x or y or z" 其中一个
 -abc menas -a -b -c 任意组合
7,The man Command
man [<chapter>] <command>
比较重要的是1,5,8 章节
man 5 passwd
man lvm
8,Navigating man Pages
arrows,pgUp,pgDown
/<text> search for text
n/N netx/previous keywords
man -k <keyword> list all matching pages
man -k passwd
9,The info Command
比man更详细
info page are structured like a web site
tab可以进入其它主题
info <command>
10,Navigating info Pages
arrows,pgUp,pgDown
Tab/Enter
n/p/u next/previous/up-one(上一层) node
s[<text>] search for text
11,Extended Documentation
/usr/share/doc
12,Red Hat Documentation
===============================================================================
Unit 3 Beowsing the Filesystem
1,Linux File Hierarchy Concepts
2,Some Important DIrectories
3,Other Important DIrectories
4,Current Working DIrectory
5,File and Directory Names
6,Absolute Pathnames
7,Relative Pathnames
8,Changing Directories
9,Listing Directory Contents
10,Copy files and Directories
11,Copy files and Directories:The Destination
12,Moving and Renaming files and Directories
13,Moving and Renaming files and Directories:The Destination
14,Creating and Removing Files
15,Creating and Removing Directories
16,Using Nautilus
17,Moving and Copying in Nuatilus
18,Determineing File Content
19,Viewing an entire Text FIle
20,Viewing Text Page by Page 1,Linux File Hierarchy Concepts
 单根目录,大小写敏感,以.开头的文件/目录是隐藏的
2,Some Important DIrectories
 /home/username
 /bin /sbin
 /media /mnt
3,Other Important DIrectories
 /etc /tmp /boot /dev /usr
4,Current Working DIrectory
 pwd
5,File and Directory Names
 Names may be up to 255 characters
 All characters are valid,except the "/"
 名字中有空格,用双引号扩起,大小写区分
6,Absolute Pathnames
 begin with a slash (/)
7,Relative Pathnames
 spectifies location relative to your current working directory
8,Changing Directories
 cd cd.. cd~
9,Listing Directory Contents
 ls [options] [files or directories]
10,Copy files and Directories
 More than one file may be copied at a time if the destination is a directory
 cp file1 file2 dest
 cp -p 不修改文件属性(时间)
 cp -r 复制目录用
11,Copy files and Directories:The Destination
 if the destination exists and is a direcory, the copy is placed there with the same name
 if the destination exists and is a file,the copy overwrites the destination file
 if the destination does not exist,the copy is created with that name
12,Moving and Renaming files and Directories
 More than one file may be moved at a time if the destination is a directory
13,Moving and Renaming files and Directories:The Destination
 if the destination exists and is a direcory, the source file or directory is moved there with the same name
 if the destination exists and is a file,the source file is moved to that filename,overwriting the file
 if the destination does not exist,the source file or directory is renamed with that name
14,Creating and Removing Files
 rm -i interactive
 rm -r recursive 目录
 rm -f force
 touch -create empty file or update file timestamps
15,Creating and Removing Directories
 mkdir
 rmdir empty directory
 rm -r 包含内容
16,Using Nautilus
 gnome graphical filesystem browser
 can run in spatial(每个目录都开一个窗口) or browser(资源管理器样式) mode
 $nautilus
17,Moving and Copying in Nuatilus
 Drag and Drop
 Left-button : move on same filesystem, copy on different filesystem
 Ctrl-Left-button : alwayls copy
 Alt-Left-button : Ask whether to copy,move or create symbolic link
18,Determineing File Content
 file [options] filename
19,Viewing an entire Text FIle
 cat [options] filename
 多个文件会连载输出
 cat -A 可以看到换行符
 cat -b 带行号
20,Viewing Text Page by Page
 less filename
 arrows / pgUp /pgDown
 /text search for text
 n -next match
 v 进入编辑模式
===============================================================================
Unit 4 - The bash SHell
1,bash introduction
2,bash heritage
3,Command Line Shortcuts: File Globbing
4,Command Line Shortcuts: The Tab Key
5,Command Line Shortcuts: history
6,Command Line Shortcuts: Tilde(~)
7,Command Line Shortcuts: Variable and Curly braces({})
8,Command Line Shortcuts: Command and Math
9,Command Line Shortcuts: Backslash(\)
10,Command Line Shortcuts: Quotes
11,History Tricks
12,Command Editing Tricks:Editing Modes
13,gonme - terminal 1,bash introduction
 "Bourne Again Shell"
 用户和kernel之间的桥梁
2,bash heritage
 unix分为两派:Sys V (sh) BSD(csh->ksh->tchsh->zsh)
3,Command Line Shortcuts: File Globbing
 * 0个或多个字符
 ? 1个字符
 []字符范围
 [^]非字符范围
4,Command Line Shortcuts: The Tab Key
 补齐未输入完全的指令 tou->touch
 pw tab一次不会补齐,再tab一次,显示所有以tab开头的指令
 文件名字也可以补齐
5,Command Line Shortcuts: history
 !指令编号
 ^2^1 把上个指令中的2改成1 用在ping中比较合适
6,Command Line Shortcuts: Tilde(~)
 回到home目录
7,Command Line Shortcuts: Variable and Curly braces({})
 echo $HOME
 touch {a,b} ->a,b
 touch a{a,b} ->aa,ab
 touch {a,b}.{1,2} -> a.1,a,2,b.1,b.2
8,Command Line Shortcuts: Command and Math
 `` 反引号取指令结果
 echo "Hostname: `hostname`" 或者
 echo "Hostname:$(hostname)"
 $[] 数学运算
 echo $[$a + $c]建立加空格
9,Command Line Shortcuts: Backslash(\)
 转义字符
 echo Your cost is $5.00
 将\放到指令最后,代表指令接到下一行(一行没有完成指令)
10,Command Line Shortcuts: Quotes
 Single quotes(')
 Double quotes(") except:$ \ ` !
 echo ** 00000 **
11,History Tricks
 up and down arrow
 CTRL+R search for a history command
 recall last argument from previous command
 ESC放开加. /ALT不放加.
 ping适用 先ping后telnet
12,Command Editing Tricks:Editing Modes
 By default,bash uses emacs-style
 set -o vi 变成vi模式 set +o vi 变回来
 set -o 可见模式
13,gonme - terminal
 Ctrl+Shift+t open a new tab
 Ctrl-pgUP/pgDn Next/Prev tab
 Alt -号码 change to N号 tab
 Ctrl+Shift+c/v Copy/Paste
 Ctrl+Shift+w open a tab
====================================================================================
Unit 5 Standard I/O and Pipes
1,Standard input and output
2,Redirecting output displayed on the terminal
3,Redirecting input and output
4,Overwriting or Appending
5,Redirecting Standard Output
6,Redirecting Standard Error
7,Redirecting Both Standard Output and Error
8,Redirecting input
9,cut
10,sort
11,Using Pipes to Connect Processes
12,Using Pipes For Mail
13,tee 1,Standard input and output
 Standard input - keyboard         0
 Standard output - terminal windows 1
 Standard error - terminal windows 2
 ls -l /dev/std*
2,Redirecting output displayed on the terminal
 find /etc -name passwd
3,Redirecting input and output
 >,>>,<
4,Overwriting or Appending
5,Redirecting Standard Output
 find /etc -name passwd 1 > stdout
 find /etc -name passwd > stdout 默认就是标准输出1
6,Redirecting Standard Error
 find /etc -name passwd 2 > stdout
7,Redirecting Both Standard Output and Error
 find /etc -name passwd 2 > error 1 > output 两个文件
 find /etc -name passwd > alloutput 2>&1
 find /etc -name passwd &> allput
8,Redirecting input
 tr 'A-Z' 'a-z' < .bash_profile
9,cut
 -f 位置
 -d 分隔符
 -c 字母数目 c4-8
10,sort
 -r 反向
 -f 忽略大小写
 -u 取消重复项
 -t 使用 x做为分隔符
 -n 数值排列
 -k POS1 按某一栏做排列
 sort -t: -k3 /etc/passwd
 sort -t: -k3 -n /etc/passwd
11,Using Pipes to Connect Processes
 ls -l | less
12,Using Pipes For Mail
 mail -s "1st mail" user2<contents.txt
 cat /var/spool/mail/user2 可以看到内容
 cat ~user2/mbox 阅读过的邮件
 ls -l | mail -s "3rd mail" user2
 cat list.txt | xargs rm -f 删除list.txt列表文件里面的每一行
 ls -l | lpr = > prn
13,tee
 资料分流
 cut -f1 -d: /etc/passwd | sort | less
 cut -f1 -d: /etc/passwd | tee cut.file | sort |tee sort.file | less 
======================================================================================
unit 6 - Users,Groups,and Permissions
1,The Linux Security Model
2,Users
3,Groups
4,The root User
5,Linux File Security
6,Permissions Types
7,Examining Permissions
8,Interpreting Permissions
9,Examining Directories
10,Processing Linux Security
11,Changing Permissions - Symbolic Method
12,Changing Permissions - Numeric Method
13,Changing Permissions - Nautilus 1,The Linux Security Model
 Users and groups are used to control access to files and resources
 Every file on the system is owned
2,Users
 uid
 /etc/passwd 7 fields
 /etc/shadow
 /home/
 /etc/passwd 将密码字段的x删除,登录无需密码.
3,Groups
 gid
 /etc/group   user2:x:501:成员列表
 /etc/gshadow group名字:group passwd
4,The root User
 Root has complete control over the system
5,Linux File Security
 owner,group,others
6,Permissions Types
 r,w,x,-
7,Examining Permissions
 ls -i
8,Interpreting Permissions
 10个字符的意义
9,Examining Directories
 ls -ld
10,Processing Linux Security
 判断过程
 是否root->uid是否相同(owner?)->gid是否相同(群组)->other
11,Changing Permissions - Symbolic Method
 chmod [=R] mode filename
12,Changing Permissions - Numeric Method
 4210
13,Changing Permissions - Nautilus
==========================================================================================
Unit 7 vi Editor Basics and Printing
1,Starting vi
2,Three Modes of vi
3,Cursor Movemnet
4,Entering insert Mode
5,Leaving insert Mode:<ESC>
6,Change,Delete,and Yank(copy):command mode
7,Put(paste):command mode
8,Undoing Changes:command mode
9,Searching for text:command mode
10,command-mode tricks
11,svageing and quiting:ex mode
12,Printing in Linux
13,Printing Commands
14,Printing Utilities 1,Starting vi
 vi filename
2,Three Modes of vi
 command mode:cursor movement,change,delete,copy,paste,search
 insert mode:(进入a,i退出ESC)type
 extended mode(:) quit,save,search and replace
3,Cursor Movemnet
 h->left,j->down,k->up,l->down
 w->word ahead,b->word back
 (->sentence back,)->sentence forward
 {->paragraph above,}->paragraph below
4,Entering insert Mode
 a(光标停在后一格),i(光标停在原地)
 A(光标停在行尾),I(光标停在行首)
 o(光标停在新增的下一空白行),O(光标停在新增的上一空白行)
5,Leaving insert Mode:<ESC>
 ESC可以多次按
6,Change,Delete,and Yank(copy):command mode
  cut  delete  yank(copy)
line  cc  dd  yy
letter  cl  dl  yl
word  cw  dw  yw
7,Put(paste):command mode
 p,P changed,deleted or copied date
 For line oriented data:
  p puts the data below the current lne
  P puts the data above the current lne
 For character oriented date:
  p puts the data after the cursor
  Pputs the data before the cursor
8,Undoing Changes:command mode
  u undo most recent change
  Ctrl-r redo last "undone" change
  U undo all changes
9,Searching for text:command mode
 /text  search downwards for "text"
 ?text  search upwards for "text"
 n continue search in the same direction
 N continue search in the opposite direction
10,command-mode tricks
 dtc delete from cursor to the letter c
 rc replace a character with c
 x delete a character
 5dd  delete 5 lines
 5yy copied 5 lines
 5x delete 5 characters
 R replace character-for-character until <ESC>
11,svageing and quiting:ex mode
 w saving
 q quitting
 ! forcing
 root可以强写只读文件
12,Printing in Linux
 CUPS
 local printer
 network printer
 documnets->queue->input filter->printer
13,Printing Commands
 BSD    System V
 lpr/lpq/lprm   lp/lpstat/cancel
 lpr filename
 lpr -Php README hp是打印机名称
 queue->/var/spool/cups
 搬移打印工作从一个队列到另一个队列 lpmove
 lpmove ok-9 hp 名字 队列
 插队lp -i17 -q51
 i代表job编号 q51设置优先权(默认都是50)
 disable ok 让打印机停用再开启/usr/bin/enable ok (必须指明路径)(第二道门)
 reject ok关闭第一道门 accept ok
14,Printing Utilities
 enscript  convert 文件 -p 新文件名
 ggv  postscript and pdf 查看
 ps2pdf/pdf2ps  ps2pdf readme.ps > rs.pdf
 mpage  print multipages per sheet
 mpage -4 r.ps > m.ps 4页合成1页
==============================================================================================
Unit 8 - The Linux Filesystem In-Depth
1,Partitions and Filesystems
2,Inodes
3,Directories
4,cp and inodes
5,mv and indoes
6,rm and inodes
7,Symbolic ( or soft ) Links
8,Hard Links
9,The Seven Fundamental Filetypes
10,Checking Free Space
11,Removable Media
12,Mounting CDs and DVDs
13,Mounting USB Media
14,Mounting Floppy Disks
15,Formatting Floppy Disks
16,Why Archive FIles
17,Creating an Archive
18,inspecting Archive
19,Extracting an Archive
20,Why use Files Compression?
21,Compression Utilities
22,Using Commpression
23,Compressing Archives
24,tar to Unformatted Floppies 1,Partitions and Filesystems
 Disk Drives are divided into partitions
 Partitions are formatted with filesystems,allowing users to store data
 one block : 4K
2,Inodes
 An inode table contains a list of all files
 An inode (index node) is an entry (metadata) in the table -->FAT
 inode-no,file type,permission,link count,uid,gid,size,time stamp....pointer(所有bloks)
 time(access time,modify time,change time)
 inode-no.->inode table->pointer->block
3,Directories
 A directory is a mapping between the human name for the file and the inode number
 ls -i可以看到每个文件对应的inode号码
4,cp and inodes
 Allocates a free inode number,placing a new entry in the inode table
 Creates a directory entry,referencing the files human file name to the inode number
 Copies date into the new file
5,mv and indoes
 if the destination of the mv command is on the same filesystem as the source:
 Creates a new directory entry with the new file name
 Deletes the old directory entry with the old file name
 Has no impact on the inode table or the location of data on the disk:: no data moved
6,rm and inodes
 Decrements the link count,thus releasing the inode number to be reused
 Place data block int the free list
 Remove the direcory entry
7,Symbolic ( or soft ) Links
 A symbolic link point to another file
 ls -s filename linkname
8,Hard Links
 cannot span drives or partitons
 ln filename [linkname] 避免重要文件被删除,同一个目录下不能建立
9,The Seven Fundamental Filetypes
 -/d/l/b/c/p/s
 /dev/initct1
10,Checking Free Space
 df ->reports disk sapce usage  per filesystem -h 以G为单位显示
 du ->per diectory -s (summary) -h 以G为单位显示
 du -h /root | less
11,Removable Media
 By default,non-root users may only mount certian deices (cd ,dvd,flppy,usb,etc)
12,Mounting CDs and DVDs
 Automatically mounted in Gnome/KDE
 reject
13,Mounting USB Media
 Detected by the kernel as scsi devices
 /dev/sdaX
 Automatically mounted in Gnome/KDE
14,Mounting Floppy Disks
 mount /media/floppy
15,Formatting Floppy Disks
 A low level format (rarely) ->fdformat /dev/fd0
 A filesystem
 mkfs -t ext2 /dev/fd0
 mke2fs /dev/fd0
16,Why Archive FIles
 Easier to backup,store
 tar archive file with the inode table
17,Creating an Archive
 tar cvf archive_name files..
18,inspecting Archive
 tar tf a.tar
 tar tvf a.tar (ls -l)
19,Extracting an Archive
 tar xvf a.tar
20,Why use Files Compression?
 Results in smaller file size
21,Compression Utilities
 gzip / gunzip
 bzip2 /bunzip2
22,Using Commpression
 gzip 文件名
 gzip -v 文件名 显示压缩比
 gzip -c 文件名 保留原来的
 gunzip 文件名
 不能压缩目录
23,Compressing Archives
 tar z for gzip
 tar j for bzip2
 tar -cvfz a.tar.gz doc
24,tar to Unformatted Floppies
 floppies can be used like tape drives
 low level format required
 file system not needed
 floppy cannot be mounted
 /dev/fd0 is the destination
 tar cvfM /dev/fd0 ~ M代表分卷
 tar xvfM /dev/fd0
==============================================================================================
Unit 9 - Configuring the bash shell
1,Configuring the bash shell
2,Variables
3,Configuring the shell:local variables
4,common local variables
5,the ps1 local variable
6,Aliases
7,Other Shell Configuration Methods
8,Configuring Commands:Environment variables
9,Common Environment variables
10,the TERM Environment variables
11,the PATH Environment variables
12,How the Shell expands the command line
13,shell startup scripts
14,login shell
15,startup script:order of execution
16,/etc/profile
17,/etc/profile.d
18,~/.bash_profile and ~/.bashrc
19,~/.hash_login 1,Configuring the bash shell
 local variables
 aliases and functions
 set
2,Variables
 two types:local and environment
 local Variables are used only by the shell
 environment Variables are passed onto other commands
 set to display all ariables
 env to display environment Variables
3,Configuring the shell:local variables
 data in shell scripts and environment settings stored in variables
 conventionally all up-case
4,common local variables
 HISTFILESIZE -> history command
 COLUMNS -> the width of the terminal
 LINES -> the height of the terminal
5,the ps1 local variable
 \d  -> today's date
 \h  -> short hostanme
 \t  -> current time
 \u  -> user name
 \W  -> current working directory
 \l  -> which tty
6,Aliases
 alias lf='ls -laF'
7,Other Shell Configuration Methods
 set -o noclobber -> do not clobber files with > and & operators 保护不被覆盖
 set -o vi
8,Configuring Commands:Environment variables
 export variablename
 unset variablename
 仅root可以unset Environment variables
9,Common Environment variables
 HOME/LANG/PWD
10,the TERM Environment variables
 TERM environment variable defines the terminal type (xterm)
 reset 重设屏幕
11,the PATH Environment variables
 which 根据PATH找可执行文件
12,How the Shell expands the command line
 split the line into shell words
 function an alias expansion
 curly brace string expansion
 tilde expansion
 parameter and variable expansion
 split the line into shell words again
 file glob expansion
 file redirection
 run the command
13,shell startup scripts
 scripts of commands executed at login
 建立自定义变量,建立环境变量,建立别名,自动执行的程序
14,login shell
 A login shell,non-login shell
15,startup script:order of execution
 login shells
     /etc/profile 用". "来调用其它脚本
        /etc/profile.d
     ~/.bash_profile
     ~/.bashrc
     /etc/bashrc
 non-login shells
    ~/.bashrc
    /etc/bashrc
     /etc/progfile.d
16,/etc/profile
 建立许多变量
17,/etc/profile.d
 应用程序需要的启动脚本,初始化一些变量
18,~/.bash_profile and ~/.bashrc
 用户偏好设置
19,~/.hash_logout
 备份文件,删除临时文件.
==============================================================================================
Unit 10 - Advanced Topics in Users,Groups and Permissions
1,User and Group ID Numbers
2,/etc/passwd,/etc/shadow, and /etc/group
3,System Users and Groups
4,Changing your identify
5,user information Commands
6,Default Permissions
7,Special Permissions
8,Special Permissions for Executables
9,Special Permissions for Directories
 
1,User and Group ID Numbers
 Napping user names to user ID numbers
 data stored on the hard disk is stored numberically
2,/etc/passwd,/etc/shadow, and /etc/group
 用户数据库
 密码是用户ID和密码MD5计算的
3,System Users and Groups
 内建的用户和群组1-499
4,Changing your identify
 su user1
 su - user1 不仅变成user1,环境变量也变成user1的 $PATH
 passwd --status user1
5,user information Commands
 whoami
 groups,id
 users,who,w(IP)
 last
6,Default Permissions
 file 666
 directories 777
 umask non-privileged 002
 umask root 022
 不可以用666-033
 umask 033 touch a.txt ls -l
7,Special Permissions
 a fourth Permission
 三种:suid,sgid,sticky
 分别借执行位三个x来标识,如果原来有X,用s表示权限,如果原来没有X,用S表示
 sticky 用t/t表示
 chmod u+s file1
 chmod o+t file2 如果file2的o里面没有x,自动变成大T
 数字代表4 2 1
 755  -> file1
 chmod 2755 file1 >加上sgid
 chmod 7755 file1 >全加上
 nautilus内也可以设置
8,Special Permissions for Executables
 suid:command run with permission of the owner of the command,not executor of the command
 ls -l /bin/ping 带有suid
 ping 192.168.0.1 -c4
 chmod u-s /bin/ping 但是o里面有x,所以其它人可用
 user1去ping
 ping:icmp open socket:operation not permitted
 sgid:command run with group affiliation of the group of the command
9,Special Permissions for Directories
 sticky bit和gid可以放到目录上
 sticky目录里面的文件只有owner和root可以删除
 ls -ld tmp 发现有sticky
 sgid目录里面只有所属群组可以建立文件
 Often both the stcky bit and the sgid permission will be set on a project directory
==============================================================================================
Unit 11 - Advanced Uses of the vi Editors (female)
1,File Repositioning
2,Screen Repositioning
3,Filtering
4,ex mode: Search and Replace
5,Advanced Reading and Saving
6,Configuring vi 1,File Repositioning
 G   -> go to last line in file
 1G   -> go to first line in file
 Ctrl -d  -> go down half a screen
 Ctrl -u  -> go up half a screen
2,Screen Repositioning
 H      -> go to first line on screen
 M  -> go to middle line on screen
 L  -> go to low line on screen
 z  -> make current line first line on screen
 z-  -> make current line last line on screen
3,Filtering
 The output of a command can be placed in the file
 !!ls -l        -> 插入文件列表
 !!date
 !}sort         ->排序
 !}fmt -w60     ->段落宽度
4,ex mode: Search and Replace
 sed
 no address -> current line only
 1,10
 1,$ or % -> all
 .,.+ 10 -> from currnet line to 10
 s/This/That    -> 替换一个
 s/This/That/g -> 这一行内所有
 1,10s/This/That/g ->前10行所有
 .,-3代表从当前行加上上三行
5,Advanced Reading and Saving
 :r file1
 :1,20w file2
 :1,$w file3 另存为
 :1,20w >> file4
 :n 下一个文件
 :rew 第一个文件
 :n# 两个文件之间切换
6,Configuring vi
 :set ignorecase 忽略大小写 n下一个
 :set noic
 :set number 行号
 :set nonu
==============================================================================================
Unit 12 - Introduction to String Processing
1,head
2,tail
3,wc
4,uniq
5,Other String Processing Tools
6,Version Comparison with diff
7,Spell Checking with aspell
8,Formatting Tools 1,head
 use -n 行数 (default 10 lines)
 use --lines 10
 use -12 filename
 适合查看文件开头的介绍部分
2,tail
 -n or --lines  or -n
 适合查看刚刚更新的文件/etc/passwd
 -f 查看文件时不关闭文件,适合查看正在更新的日志
 cat /var/log/messages
3,wc
 -l for only line count
 -w word
 -c character
 wc README
 207 1924 13001
4,uniq 去掉相邻的重复行
 sort file1 |uniq = sort -u
 -c count numbers of 重复行
5,Other String Processing Tools
 paste 水平合并多个文件(tab)分隔
 paste fiel1 fiel2 > file3
 cat file1 file2 >file3 垂直合并
 tr替换
 tr 'A-Z' 'a-z' <a.txt
 例子:unix和dos下文本文件的段落符$ \r
 cat -A file4
 a$
 a$$
 cat -A file4 | tr '$' '\r'>file5
 a^M$
 aa^M$
 unix2dos file4
6,Version Comparison with diff
 < indicates line in first file 在第一个文件中出现
 > indicates line in second file
 sdiff ABC abc 以对比形式出现结果
7,Spell Checking with aspell
 aspell check file1
 less /usr/share/dict/words
 cat /usr/share/dict/words | wc l