rche 033----unit9 config the bash shell

unit9     config the bash shell

.local variables
.aliases and functions
.the set command
.environment variables

variables: A variable is a label that has a value
        .used to config the shell or other programs
        .variables are resided in memory
        .two types :local and environment
        .local varibales are used only by the shell
        .environment variables are passed onto other commamd
   
          .display variables and values using
               .set to display all variables
               .env to display environment variables
              
  set |more  查看系统中所有的变量
 
  env | more   ===环境 变量
 
 configuring the shell: local variables
   
     .Data in shell scripts and environment settings stored in variables
     .conventionally all  upper-case
     .setting     variable value
      $ FAV_COLOR=blue
      set |more 查看
   .to retrieve variable value.use $ before variable name
  
        echo $FAV_COLOR
        blue          
       
       
4,common local variables       
       
  .histfilesize   determines how many commands to be saved
                  in the history file on logout
  .columns        sets the width of the terminal
  .lines          sets the height of the terminal
 
 
5,ps1 local variable 
  . ps1  sets the prompt
      .\d  today is date
      .\h  short hostname
      .\t  current time
      .\u  user name
      .\w  current working directory
      .\!  the history number of current command
      .\$  shows $ if you are a none-privileged user and a # if you are a privileged user
      .\l  the basename of the shell is terminal device name
     
[root@mycentos ~]# echo $PS1
[\u@\h \W]\$
[root@mycentos ~]#
     
 PS1='[\u@\h \w \l \d \t \!]\$'
[root@mycentos ~ 0 Tue Apr 28 03:47:37 342]#
 
 PS1='[\u@\h \w tty\l \d \t \!]\$'
[root@mycentos ~ tty0 Tue Apr 28 03:48:19 343]#

 

6,Aliases
        .Aliases let you create shortcuts to commands
           $ alias if='ls -laF'
        .USE alias by itself to see all set aliases
        .use alias followde by an alias name to see alias           value   $alias if
                  alias if='ls -laF'
        alias   显示系统中的别名
        alias   if
                
.set -o noclobber
.set -o vi

      [root@mycentos ~]#ls -l doc1
total 28
-rw-r--r-- 1 root root  1 Apr 28 03:54 test1.txt
-rw-r--r-- 1 root root 60 Apr 27 23:16 test2.txt
-rw-r--r-- 1 root root 42 Apr 27 23:16 test3.txt
-rw-r--r-- 1 root root  0 Apr 27 23:14 text1.txt
[root@mycentos ~]#cal > doc1/test1.txt
[root@mycentos ~]#cat doc1/test1.txt
     April 2009    
Su Mo Tu We Th Fr Sa
          1  2  3  4
 5  6  7  8  9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30

[root@mycentos ~]#ca >& doc1/text1.txt 正确和错误的信息传入到text1.txt
[root@mycentos ~]#cat doc1/text1.txt
-bash: ca: command not found
[root@mycentos ~]#set -o noclobber=====保留原来的内容
[root@mycentos ~]#cal > doc1/text1.txt
-bash: doc1/text1.txt: cannot overwrite existing file

[root@mycentos ~]#cal >> doc1/text1.txt
[root@mycentos ~]#cat doc1/text1.txt

-bash: ca: command not found
     April 2009    
Su Mo Tu We Th Fr Sa
          1  2  3  4
 5  6  7  8  9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30

 

config commands:   Environment -----全局变量Variables============================================环境变量

.shell variables exist only in current shell environment
.Environment variables passed to subshells
.shell variables can be exported into environment
      $ export variable name  ===升级成环境变量 

 

[root@mycentos ~]#set |more============================查看新建的变数：FAV_COLOR=blue
BASH=/bin/bash
BASH_ARGC=()
BASH_ARGV=()
BASH_LINENO=()
BASH_SOURCE=()
BASH_VERSINFO=([0]="3" [1]="2" [2]="25" [3]="1" [4]="release" [5]="i686-redhat-linu
x-gnu")
BASH_VERSION='3.2.25(1)-release'
COLORS=/etc/DIR_COLORS
COLUMNS=83
CVS_RSH=ssh
DIRSTACK=()
EUID=0
FAV_COLOR=blue==========================存在的
GROUPS=()
G_BROKEN_FILENAMES=1
HISTFILE=/root/.bash_history
HISTFILESIZE=1000
HISTSIZE=1000
HOME=/root
HOSTNAME=mycentos
HOSTTYPE=i686
IFS=$' \t\n'
INPUTRC=/etc/inputrc
LANG=en_US.UTF-8
LESSOPEN='|/usr/bin/lesspipe.sh %s'
LINES=38
LOGNAME=root
LS_COLORS='no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:cd=40;33;01:
or=01;05;37;41:mi=01;05;37;41:ex=01;32:*.cmd=01;32:*.exe=01;32:*.com=01;32:*.btm=01
;32:*.bat=01;32:*.sh=01;32:*.csh=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01
;31:*.lzh=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*
.tz=01;31:*.rpm=01;31:*.cpio=01;31:*.jpg=01;35:*.gif=01;35:*.bmp=01;35:*.xbm=01;35:
*.xpm=01;35:*.png=01;35:*.tif=01;35:'
MACHTYPE=i686-redhat-linux-gnu
MAIL=/var/spool/mail/root
MAILCHECK=60
OPTERR=1
OPTIND=1
OSTYPE=linux-gnu
PATH=/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin
:/usr/sbin:/usr/bin:/root/bin
PIPESTATUS=([0]="0")
PPID=2865
PS1='[\u@\h \w]\$'
PS2='> '
PS4='+ '
PWD=/root
SHELL=/bin/bash
SHELLOPTS=braceexpand:emacs:hashall:histexpand:history:interactive-comments:monitor
:noclobber
SHLVL=1
SSH_AUTH_SOCK=/tmp/ssh-GuqqAj2865/agent.2865
SSH_CLIENT='192.168.1.100 1273 22'
SSH_CONNECTION='192.168.1.100 1273 192.168.1.199 22'
SSH_TTY=/dev/pts/0
TERM=vt100
UID=0
USER=root
_=clear
consoletype=pty
You have new mail in /var/spool/mail/root

[root@mycentos ~]#useradd u1
[root@mycentos ~]#useradd u2
[root@mycentos ~]#su u1
[u1@mycentos root]$ whoami==================================到u1用户上
u1
[u1@mycentos root]$ set | more  =============查看有没有FAV_COLOR
BASH=/bin/bash
BASH_ARGC=()
BASH_ARGV=()
BASH_LINENO=()
BASH_SOURCE=()
BASH_VERSINFO=([0]="3" [1]="2" [2]="25" [3]="1" [4]="release" [5]="i686-redhat-linu
x-gnu")
BASH_VERSION='3.2.25(1)-release'
COLORS=/etc/DIR_COLORS
COLUMNS=83
CVS_RSH=ssh             ==============================没有
DIRSTACK=()
EUID=500
GROUPS=()
G_BROKEN_FILENAMES=1
HISTFILE=/home/u1/.bash_history
HISTFILESIZE=1000
HISTSIZE=1000
HOME=/home/u1
HOSTNAME=mycentos
HOSTTYPE=i686
IFS=$' \t\n'
INPUTRC=/etc/inputrc
LANG=en_US.UTF-8
LESSOPEN='|/usr/bin/lesspipe.sh %s'
LINES=38
LOGNAME=u1
LS_COLORS='no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:cd=40;33;01:
or=01;05;37;41:mi=01;05;37;41:ex=01;32:*.cmd=01;32:*.exe=01;32:*.com=01;32:*.btm=01
;32:*.bat=01;32:*.sh=01;32:*.csh=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01
;31:*.lzh=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*
.tz=01;31:*.rpm=01;31:*.cpio=01;31:*.jpg=01;35:*.gif=01;35:*.bmp=01;35:*.xbm=01;35:
*.xpm=01;35:*.png=01;35:*.tif=01;35:'
MACHTYPE=i686-redhat-linux-gnu
MAIL=/var/spool/mail/root
MAILCHECK=60
OPTERR=1
OPTIND=1
OSTYPE=linux-gnu
PATH=/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin
:/usr/sbin:/usr/bin:/root/bin
PIPESTATUS=([0]="0")
PPID=14394
PS1='[\u@\h \W]\$ '
PS2='> '
PS4='+ '
PWD=/root
SHELL=/bin/bash
SHELLOPTS=braceexpand:emacs:hashall:histexpand:history:interactive-comments:monitor
SHLVL=2
SSH_AUTH_SOCK=/tmp/ssh-GuqqAj2865/agent.2865
SSH_CLIENT='192.168.1.100 1273 22'
SSH_CONNECTION='192.168.1.100 1273 192.168.1.199 22'
SSH_TTY=/dev/pts/0
TERM=vt100
UID=500
USER=u1
_=whoami
consoletype=pty
[u1@mycentos root]$ exit
exit

[root@mycentos ~]#export FAV_COLOR=============================把此变数导出为环境变量
[root@mycentos ~]#su u1           ==============================再次进入u1用户查看
[u1@mycentos root]$ set |more
BASH=/bin/bash
BASH_ARGC=()
BASH_ARGV=()
BASH_LINENO=()
BASH_SOURCE=()
BASH_VERSINFO=([0]="3" [1]="2" [2]="25" [3]="1" [4]="release" [5]="i686-redhat-linu
x-gnu")
BASH_VERSION='3.2.25(1)-release'
COLORS=/etc/DIR_COLORS
COLUMNS=83
CVS_RSH=ssh
DIRSTACK=()
EUID=500
FAV_COLOR=blue                  =================================已经出现了此变数
GROUPS=()
G_BROKEN_FILENAMES=1
HISTFILE=/home/u1/.bash_history
HISTFILESIZE=1000
HISTSIZE=1000
HOME=/home/u1
HOSTNAME=mycentos
HOSTTYPE=i686
IFS=$' \t\n'
INPUTRC=/etc/inputrc
LANG=en_US.UTF-8
LESSOPEN='|/usr/bin/lesspipe.sh %s'
LINES=38
LOGNAME=u1
LS_COLORS='no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:cd=40;33;01:
or=01;05;37;41:mi=01;05;37;41:ex=01;32:*.cmd=01;32:*.exe=01;32:*.com=01;32:*.btm=01
;32:*.bat=01;32:*.sh=01;32:*.csh=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01
;31:*.lzh=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*
.tz=01;31:*.rpm=01;31:*.cpio=01;31:*.jpg=01;35:*.gif=01;35:*.bmp=01;35:*.xbm=01;35:
*.xpm=01;35:*.png=01;35:*.tif=01;35:'
MACHTYPE=i686-redhat-linux-gnu
MAIL=/var/spool/mail/root
MAILCHECK=60
OPTERR=1
OPTIND=1
OSTYPE=linux-gnu
PATH=/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin
:/usr/sbin:/usr/bin:/root/bin
PIPESTATUS=([0]="0")
PPID=19533
PS1='[\u@\h \W]\$ '
PS2='> '
PS4='+ '
PWD=/root
SHELL=/bin/bash
SHELLOPTS=braceexpand:emacs:hashall:histexpand:history:interactive-comments:monitor
SHLVL=2
SSH_AUTH_SOCK=/tmp/ssh-GuqqAj2865/agent.2865
SSH_CLIENT='192.168.1.100 1273 22'
SSH_CONNECTION='192.168.1.100 1273 192.168.1.199 22'
SSH_TTY=/dev/pts/0
TERM=vt100
UID=500
USER=u1
_=/etc/bashrc
consoletype=pty
[u1@mycentos root]$ exit
exit
[root@mycentos ~]#export A=1       =====================将变数A导出为环境变量
[root@mycentos ~]#set |more
A=1=======================================root用户中已经存在了
BASH=/bin/bash
BASH_ARGC=()
BASH_ARGV=()
BASH_LINENO=()
BASH_SOURCE=()
BASH_VERSINFO=([0]="3" [1]="2" [2]="25" [3]="1" [4]="release" [5]="i686-redhat-linu
x-gnu")
BASH_VERSION='3.2.25(1)-release'
COLORS=/etc/DIR_COLORS
COLUMNS=83
CVS_RSH=ssh
DIRSTACK=()
EUID=0
FAV_COLOR=blue
GROUPS=()
G_BROKEN_FILENAMES=1
HISTFILE=/root/.bash_history
HISTFILESIZE=1000
HISTSIZE=1000
HOME=/root
HOSTNAME=mycentos
HOSTTYPE=i686
IFS=$' \t\n'
INPUTRC=/etc/inputrc
LANG=en_US.UTF-8
LESSOPEN='|/usr/bin/lesspipe.sh %s'
LINES=38
LOGNAME=root
LS_COLORS='no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:cd=40;33;01:
or=01;05;37;41:mi=01;05;37;41:ex=01;32:*.cmd=01;32:*.exe=01;32:*.com=01;32:*.btm=01
;32:*.bat=01;32:*.sh=01;32:*.csh=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01
;31:*.lzh=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*
.tz=01;31:*.rpm=01;31:*.cpio=01;31:*.jpg=01;35:*.gif=01;35:*.bmp=01;35:*.xbm=01;35:
*.xpm=01;35:*.png=01;35:*.tif=01;35:'
MACHTYPE=i686-redhat-linux-gnu
MAIL=/var/spool/mail/root
MAILCHECK=60
OPTERR=1
OPTIND=1
OSTYPE=linux-gnu
PATH=/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin
:/usr/sbin:/usr/bin:/root/bin
PIPESTATUS=([0]="0")
PPID=2865
PS1='[\u@\h \w]\$'
PS2='> '
PS4='+ '
PWD=/root
SHELL=/bin/bash
SHELLOPTS=braceexpand:emacs:hashall:histexpand:history:interactive-comments:monitor
:noclobber
SHLVL=1
SSH_AUTH_SOCK=/tmp/ssh-GuqqAj2865/agent.2865
SSH_CLIENT='192.168.1.100 1273 22'
SSH_CONNECTION='192.168.1.100 1273 192.168.1.199 22'
SSH_TTY=/dev/pts/0
TERM=vt100
UID=0
USER=root
_=A
consoletype=pty
[root@mycentos ~]#su u1                    =================切换到u1用户查看
[u1@mycentos root]$ set | more
A=1                                        ==================也出现了
BASH=/bin/bash
BASH_ARGC=()
BASH_ARGV=()
BASH_LINENO=()
BASH_SOURCE=()
BASH_VERSINFO=([0]="3" [1]="2" [2]="25" [3]="1" [4]="release" [5]="i686-redhat-linu
x-gnu")
BASH_VERSION='3.2.25(1)-release'
COLORS=/etc/DIR_COLORS
COLUMNS=83
CVS_RSH=ssh
DIRSTACK=()
EUID=500
FAV_COLOR=blue
GROUPS=()
G_BROKEN_FILENAMES=1
HISTFILE=/home/u1/.bash_history
HISTFILESIZE=1000
HISTSIZE=1000
HOME=/home/u1
HOSTNAME=mycentos
HOSTTYPE=i686
IFS=$' \t\n'
INPUTRC=/etc/inputrc
LANG=en_US.UTF-8
LESSOPEN='|/usr/bin/lesspipe.sh %s'
LINES=38
LOGNAME=u1
LS_COLORS='no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:cd=40;33;01:
or=01;05;37;41:mi=01;05;37;41:ex=01;32:*.cmd=01;32:*.exe=01;32:*.com=01;32:*.btm=01
;32:*.bat=01;32:*.sh=01;32:*.csh=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01
;31:*.lzh=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*
.tz=01;31:*.rpm=01;31:*.cpio=01;31:*.jpg=01;35:*.gif=01;35:*.bmp=01;35:*.xbm=01;35:
*.xpm=01;35:*.png=01;35:*.tif=01;35:'
MACHTYPE=i686-redhat-linux-gnu
MAIL=/var/spool/mail/root
MAILCHECK=60
OPTERR=1
OPTIND=1
OSTYPE=linux-gnu
PATH=/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin
:/usr/sbin:/usr/bin:/root/bin
PIPESTATUS=([0]="0")
PPID=25759
PS1='[\u@\h \W]\$ '
PS2='> '
PS4='+ '
PWD=/root
SHELL=/bin/bash
SHELLOPTS=braceexpand:emacs:hashall:histexpand:history:interactive-comments:monitor
SHLVL=2
SSH_AUTH_SOCK=/tmp/ssh-GuqqAj2865/agent.2865
SSH_CLIENT='192.168.1.100 1273 22'
SSH_CONNECTION='192.168.1.100 1273 192.168.1.199 22'
SSH_TTY=/dev/pts/0
TERM=vt100
UID=500
USER=u1
_=/etc/bashrc
consoletype=pty
[u1@mycentos root]$ exit
exit
          
          
 unset  FAV_COLOR ==================================
 
 在普通用户中删除变数 不会影响到其他的用户变数
 
 但是如果在root下删除变数的话，将涉及到其他的用户
 
         
          
  常见的环境变量：==========================
        .HOME  用户的主目录
        .LANG  设置用户的显示语言
        .PWD    当前工作目录    
  
  
   TERM   变数
  
   .TERM
   .reset
  
  
   path 环境变数  ======系统默认路径
  
   .path   系统预设路径
  
   [root@mycentos ~]#echo $PATH
/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin
[root@mycentos ~]#PATH=$PATH:.
[root@mycentos ~]#echo $PATH
/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin:.

   .   which   
  
  
  
   HOw the shell expands the command line-----------------
  
   .A simplification
      .split the line into shell words
         ' " | & ; ()
      .function and alias
      .curly brace string expansion
        {,}
      .tilde     家目录
      .file rediretion
        .> >> < << 2< 2>
       
       
       
  shell starup scripts===========================     
       
作用：
     .scripts of commands executed at login
     .user include:
        .config the shell by setting local variables or running the set commands
        .config other programs through envrionment variables
        .establish aliases
        .run programs on startup
       
       
 LOGin   shells=========登陆触发的SHELL
      .login shells
        ./etc/profile       for i in /etc/profile.d/*.sh ; do    ===========================
        . $i
    fi
done
            ./etc/profile.d  =======================
           
         .~/.bash_profile     =====================
        
  [root@mycentos ~]#cat ~/.bash_profile
# .bash_profile

# Get the aliases and functions
if [ -f ~/.bashrc ]; then
        . ~/.bashrc
fi

# User specific environment and startup programs

PATH=$PATH:$HOME/bin

export PATH
unset USERNAME
              .~/.bashrc==========================
[root@mycentos ~]#cat  ~/.bashrc
# .bashrc

# User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'

# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi
                   . /etc/bashrc==============
        
         编辑每个文件 加上 echo /etc/profile
                         
                           echo ~/.bash_profile
                           echo ~/.bashrc
                           echo ./etc/bashrc
      
      
       non-login shells   ==================
      
       .~/.bashrc  启动时执行
            ./etc/bashrc
                ./etc/progile.d
       编辑 vi ~/.bash_profile
            vi ~/.bashrc           =========
           
           
           
           
           
           
           
16   /etc/profile=========================
        .login shell is started  run
        .only runs for login shells
        .non-login shells do not invoke this script
        .this script will set a series of variables including PATH,USER,LOGNAME ,MAIL ,HOSTNAME,HISTSIZE,AND INPUTC
       
              
17                           /etc/profile.d
       .应用程序用到得启动脚本
       .建立变数和初始化的程序
      
      
18       ~/.bash_profile and ~/.bashrc
       存放用户自已的设定，包含变数，别名
       date 
      
      
19       ~/.bash_logout
      
        存放在home 目录中
          登出所使用的应用程序
                make backups of files
                delete temporary files
                display date and time of logout
   
                                 

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