RHCE笔记整理－RH033.Unit4-The Bash shell

RHCE笔记整理－RH033.Unit4-The Bash shell

1. Bash :Bourne Again Shell
   作用：将用户输入的指令解析成linux kernel能够识别的语言，是用户与系统勾通的桥梁。
2. Bash 历史
          |--System V:sh－－－－－－－－－>Bash
   Unix|                                                 |
   

                 |--BSD:csh-->ksh                      |
                                        tchsh------------|
                                        zsh
    3. File Globbing

• Globbing is wildcard expansion

            *        mathes zero or more characters
            ?        matches any single character
            [a-z]    matches a range of characters
            [^a-z]    matches all except the range
    4. The Tab Key
    5. History
        Command:history
        Usage:

• history命令结果 会输出指令的序号和指令的名称，要使用某一序号的指令，可进行如下操作：！指令序号
• 要修改上一条指令可进行操作：^source^dest
  例：＃ping 192.168.1.123
         #^123^1
         则修改后的指令为ping 192.168.1.1

    6. The Use Of Tilde(~)

• Back to home directory
  $cd ~
• change to other user's home directory
  $cd ~username

    7.如何在指令里使用变数及｛｝
    8. 如何有摊中加入其它指令来显示电脑信息及用指令进行数学运算

• Command output      '' or $()
  例：＄echo "Hostname:`hostname`"
     or $echo "Hostname:$(hostname)"
• 数学运算：＄［］
  例：＄a=3
         $b=5
         $c=7
         $echo $[$a+$b]   //a＋b
         $echo $[$a**$b]  //a的b次方
  建议使用时各参数都用空白隔开，这是标准的语法，各平台上都可以使用

    9. Backslash

• Backslash is the escape character
  例：$echo Your cost is $5.00
        $Your cost is .00
        $echo Your cost is /$5.00
        $Your cost is $5.00

    10. The use of quotes

• quoting prevents expansion
  
  • Single quotes(`)      inhibit  all expansion
  • Double quotes(")    inhibit all expansion except
    
    • ＄
    • /
    • ｀
    • ！

    11. History  Tricks

• use up and down to sroll through previous commands
• type <CTRL－R＞ to search ro command
• To recall last argument from previous commands:
  ＜esc>.      先按ESC，放开后再按“。”
  ＜Alt-.>     同时按下Alt+.

    12. Command Editing Tricks

• By default bsh uses emacs-style
• type "set-o vi" to change keybinding ro vi-style
  
  • set -o  查看电脑上的设定
  • 切换编辑模式：
    set -o vi 把默认的编辑器改为vi，其中-o表示“减off" 即为“on"
  
  

    13. Gnome-terminal

• <ctrl+shift+t>     open a new tab
• <ctrl+PgUp/PgDn>    Next/Previous tab
• <alt-"N">                   change to goto "N" tab
• <ctrl+shift+c/v>     copy/paste
• <ctrl+shift+w>        close a tab