當你登入LINUX 後會有提示你的電腦是root@localhost #       ..................... 如何改變?

1. 看目前的提示字元
    echo $PS1
2. 改變方法:
    PS1="IP:1.88_\\u@\\w\\$ "

3.要一登入就改變的話需要修改下面檔案
   # vi /etc/bashrc

4.可用的參數如下:
    * \a : an ASCII bell character (07)
    * \d : the date in "Weekday Month Date" format (e.g., "Tue May 26")
    * \D{format} : the format is passed to strftime(3) and the result is inserted into the prompt string; an empty format results in a locale-specific time representation. The braces are required
    * \e : an ASCII escape character (033)
    * \h : the hostname up to the first '.'
    * \H : the hostname
    * \j : the number of jobs currently managed by the shell
    * \l : the basename of the shell’s terminal device name
    * \n : newline
    * \r : carriage return
    * \s : the name of the shell, the basename of $0 (the portion following the final slash)
    * \t : the current time in 24-hour HH:MM:SS format
    * \T : the current time in 12-hour HH:MM:SS format
    * \@ : the current time in 12-hour am/pm format
    * \A : the current time in 24-hour HH:MM format
    * \u : the username of the current user
    * \v : the version of bash (e.g., 2.00)
    * \V : the release of bash, version + patch level (e.g., 2.00.0)
    * \w : the current working directory, with $HOME abbreviated with a tilde
    * \W : the basename of the current working directory, with $HOME abbreviated with a tilde
    * \! : the history number of this command
    * \# : the command number of this command
    * \$ : if the effective UID is 0, a #, otherwise a $
    * \nnn : the character corresponding to the octal number nnn
    * \\ : a backslash
    * \[ : begin a sequence of non-printing characters, which could be used to embed a terminal control sequence into the prompt
    * \] : end a sequence of non-printing characters

5. 抓出電腦的目前IP位置並再登入後自動放到提示字元

    5.1 抓出ip
          ifconfig eth0 | grep "inet addr" | cut -d":" -f2 |cut -d" " -f1
    5.2 修改自動抓eth0 IP位置: 將 /etc/bashrec 作如下的改變
           5.2.1 將下面這行前面加# 註解起來

           #[ "$PS1" = "\\s-\\v\\\$ " ] && PS1="[\u@\h \W]\\$ "
          5.2.2 加入下面這兩行 ，自動的去抓IP位置

           IPADDR="$(ifconfig eth0 | grep "inet addr" | cut -d":" -f2 |cut -d" " -f1)"
          [ "$PS1" = "\\s-\\v\\\$ " ] && PS1="[$IPADDR:\u@\h \w]\\$ "
    5.3 重新登入後就可以用了，結果大約如下(每台電腦的ip不同)
          [192.168.1.11:root@localhost /etc]#