Linux学习笔记 1 环境变量 2 vi命令

1 环境变量篇

1.1  修改 查看 生效 系统环境变量

    1 涉及系统环境变量的文件   -->  .bash_profile

　　　　　　　　　　　　　　 -->　/etc/profile

    2 该文件位置 /root/.bash_profile

    3 文件编辑器打开  vi .bash_profile

    4 文件末尾加入 

                    

JAVA_HOME = /usr/share/jdk 1.6.0
PATH = $JAVA_HOME/bin:$PATH
CLASS_PATH=.$JAVA_HOME/lib/dt.jar：
$JAVA_HOME/lib/tools.jar

export JAVA_HOME
export PATH
export CLASSPATH

5 文件生效
       source /root/.bash_profile
6 验证环境变量
      export JAVA_HOME
         echo $JAVA_HOME

VI 命令篇章
 输入指令 a 
  退出指令 :q  强退：q!   保存且退出 :wq
                                    存成新文件  :w newfile

查找指令  : ？____   <要查找的单词>
                 /  ____  要查的词
           n    finding the dedicate word then moving to the next
                N    oppersite direction
                :set nu <---show the line number  
                :set nonu <---remove line number


direction :
                 k
             h   j  l

input: i  insert in front of the cursor 
         a insert behind the cursor
         o  insert in the next line of the cursor 

delete:
             x:delete the char of the cursor
            X :delete the char of the cursor

            dd:delete the current row
            5dd:delete the currrent line and the next 5 line
            :1,5d delete1 to 5 line
            x delete one charactor


vi substitute
:s /cici/titi         replace the line cici with titi
:s/cici/titi/g       replace all the cici with titi in the current line
:n,$s/cici/titi    the line n to the last line.each line cici replace with titi
:n,$s /cici/titi/g  the line n to the last line.each line cici replace with titi
:.,$s/cici/titi     replace all the words in the passages from the first line 
                     to the last line
 
repalce confirmation command.adding character c behind the comma

:s/cici/titi/gc  all the cici replace with titi  + confirmation
show line number :set nu


dw  delete current words
3dw delete 3 words

copy and attach

yw  copy word
y5w copy all 5 words
yy copy all the line 
5yy copy 5 lines
p copy after the current line
:1,2co3 copy from line1 to line2 after line 3
:4,5m6
          1          1
          2          2
          3          3
          4          6
          5          4
          6          5

location command
              gg moving to the front of the file
              G moving to the end of file 
              :20 moving to line 20
              J  merge 2 line
              shift + 8 :
                             finding the word which is in the position of cursor