Linux 系统通配符

系统正则符号

1. 系统通配符号:

   • --- 匹配所有内容
     ls -l /oldboy/.txt --- 匹配以.txt结尾信息进行详细显示
     rm -rf /oldboy/ --- 删除oldboy目录中所有信息, 但是默认无法删除隐藏文件
     rm -f /oldboy/.old.txt --- 删除以old开头 .txt结尾的所有隐藏文件
     find /oldboy -name ".txt"
     find /oldboy -name "oldboy"
     find /oldboy -name "old.txt"1
     系统正则符号: grep sed awk
     基础正则: basic regular expression BRE
     扩展正则: extended regular expression ERE

   终极目标:

   1. 文件test.txt
      张三 110106198803076651
      李四 106106199903076651
      王五 oldboy

   grep -vE "[0-9]+" test.txt

   王五 oldboy
   文件内容做修改
   张三 110106198803076651
   李四 106106199903076651
   王五 10101010100101
   周六 101010101010220101010
   如何取出IP地址信息

   基础正则:
   ^ --- 以什么开头的信息
   # ll /etc/|grep "^d"
   drwxr-xr-x. 3 root root 101 Jul 3 20:25 abrt
   drwxr-xr-x. 2 root root 252 Jul 17 18:13 alternatives
   drwxr-x---. 3 root root 43 Jul 3 20:26 audisp
   ' /etc/selinux/config
   SELINUX=disabled
   SELINUXTYPE=targeted
   说明: 如果结尾有空格信息, 过滤是会出现异常
   利用底行模式 :set list 可以查看结尾空格信息
   利用命令查看 cat -A /etc/selinux/config
   问题: 将以点结尾的信息过滤出来:
   grep '. --- 空行信息
   grep -v "^$" /etc/selinux/config

   . --- 匹配任意一个且只有一个字符
   grep "^." /etc/selinux/config --- 匹配任意一个以什么开头的字符
   grep ".$" /etc/selinux/config --- 匹配任意一个以什么结尾的字符
   grep "." /etc/selinux/config --- 匹配整个文件所有任意字符
   总结匹配筛选文件信息:
   01. 会按照行进行匹配
   02. 会匹配信息贪婪特性
   03. 利用grep -o可以查看匹配信息的过程

   • --- 匹配前一个字符连续出现0次或者多次
     创建一个测试文件:
     创建测试文件:
     I am oldboy teacher!
     I teach linux.

     I like badminton ball ,billiard ball and chinese chess!
     my blog is http://oldboy.blog.51cto.com
     our site is http://www.etiantian.org
     my qq num is 49000448.

     not 4900000448.
     my god ,i am not oldbey,but OLDBOY!

    匹配文件中数字0信息
    [root@oldboyedu oldboy]# grep "0*" oldboy.txt 
    I am oldboy teacher!
    I teach linux.
    
    I like badminton ball ,billiard ball and chinese chess!
    my blog is http://oldboy.blog.51cto.com
    our site is http://www.etiantian.org
    my qq num is 49000448.
    
    not 4900000448.
    my god ,i am not oldbey,but OLDBOY!
    [root@oldboyedu oldboy]# grep -o "0*" oldboy.txt 
    000
    00000

.*  --- 匹配文件中所有信息
    [root@oldboyedu oldboy]# grep  ".*" oldboy.txt -o
    I am oldboy teacher!
    I teach linux.
    I like badminton ball ,billiard ball and chinese chess!
    my blog is http://oldboy.blog.51cto.com
    our site is http://www.etiantian.org
    my qq num is 49000448.
    not 4900000448.
    my god ,i am not oldbey,but OLDBOY!
[]  --- 匹配中括号中任意一个字符
    [root@oldboyedu oldboy]# grep "ba" oldboy.txt     --- 表示过滤一个字符串
    I like badminton ball ,billiard ball and chinese chess!
    [root@oldboyedu oldboy]# grep "[bac]" oldboy.txt 
    I am oldboy teacher!
    I teach linux.
    I like badminton ball ,billiard ball and chinese chess!
    my blog is http://oldboy.blog.51cto.com
    our site is http://www.etiantian.org
    my god ,i am not oldbey,but OLDBOY!
    
    过滤出所有小写字母:
    grep "[a-z]" oldboy.txt     --- 过滤小写字母
    grep "[A-Z]" oldboy.txt     --- 过滤大写字母
    grep "[a-zA-Z]" oldboy.txt  --- 过滤所有字母
    grep "[a-Z]" oldboy.txt     --- 过滤所有字母 
    grep -i "[a-z]" oldboy.txt  --- grep忽略大小写进行过滤
[^] --- 将指定字符信息,进行取反过滤
    [root@oldboyedu oldboy]# grep -v "[a-Z]" oldboy.txt