一、补充

1.find -ls

系统文件属性 (文件类型 权限信息 用户信息 inode/block 硬链接和软链接)
find -ls --- 找到数据之后显示数据的属性信息

二、系统通配符号:

1.* --- 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"

2.{} --- 匹配序列信息

数字序列:
字母序列:
组合序列:
echo A{,2}   ---      A                                                         A2
                  /oldboy/oldboy01/oldboy02/oldboy03/oldboy04/oldboy.txt        .bak
快速备份数据                
cp /oldboy/oldboy01/oldboy02/oldboy03/oldboy04/oldboy.txt{,.bak}
cp /oldboy/oldboy01/oldboy02/oldboy03/oldboy04/oldboy.txt  /oldboy/oldboy01/oldboy02/oldboy03/oldboy04/oldboy.txt.bak
快速还原数据
cp /oldboy/oldboy01/oldboy02/oldboy03/oldboy04/oldboy.txt{.bak,}
cp /oldboy/oldboy01/oldboy02/oldboy03/oldboy04/oldboy.txt.bak  /oldboy/oldboy01/oldboy02/oldboy03/oldboy04/oldboy.txt
cp messages{-20190707,}

三、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

a.基础正则:

1.^ --- 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

2.$ --- 以什么结尾的信息

    # grep 'd$' /etc/selinux/config
    SELINUX=disabled
    SELINUXTYPE=targeted
    说明: 如果结尾有空格信息, 过滤是会出现异常
          利用底行模式 :set list 可以查看结尾空格信息
          利用命令查看 cat -A /etc/selinux/config
    问题: 将以点结尾的信息过滤出来:
    grep '\.$' /etc/selinux/config
    # This file controls the state of SELinux on the system.
    #     enforcing - SELinux security policy is enforced.
    #     permissive - SELinux prints warnings insteadof enforcing.
    #     disabled- No SELinux policy is loaded.
    #     minimum - Modification of targetedpolicy. Only selectedprocesses are protected.
    #     mls - Multi Level Security protection.

3.\ (不属于正则) --- 转义符号

    01. 将有特殊意义的符号, 还原本身符号意义
    02. 将没有意义的字符,变为有意义
    \r \n  --- 换行符
    \t     --- 指表符
    03. 取消别名功能
    [root@oldboyedu ~]# echo -e "oldboy01\noldboy02" >oldboy.txt
    [root@oldboyedu ~]# cat oldboy.txt 
    oldboy01
    oldboy02

4.^$ --- 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

5.* --- 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

6..* --- 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!

7.[] --- 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

8.[^] --- 将指定字符信息,进行取反过滤

    [root@oldboyedu oldboy]# grep -v "[a-Z]" oldboy.txt

    [root@oldboyedu oldboy]# grep  "[^a-Z]" 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!

b.系统扩展正则 (高级符号) grep --> egrep/grep -E sed --> sed -r

1.+ --- 匹配前一个字符连续出现1次或者多次

    # 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!
    # egrep "0+" oldboy.txt 
    our site is 0 http://www.etiantian.org
    my qq num is 49000448.
    not 4900000448.

2.| --- 匹配多个字符串信息

    匹配oldboy和oldbey单词信息
    grep "oldb[oe]y" oldboy.txt
    grep "oldb.y" oldboy.txt
    egrep "oldboy|oldbey" oldboy.txt
    企业应用: 配置文件有注释有空行, 如何进行取消
    grep -vE "^$|^#" /etc/services

3.() --- 将多个字符信息进行整合过滤 难点

        实现后项引用前项进行替换      常用
    第一个作用实践说明
    [root@oldboyedu oldboy]# grep [old] 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 0 http://www.etiantian.org
    not 4900000448.
    my god ,i am not oldbey,but OLDBOY!
    [root@oldboyedu oldboy]# egrep "(old)" oldboy.txt 
    I am oldboy teacher!
    my blog is http://oldboy.blog.51cto.com
    my god ,i am not oldbey,but OLDBOY! 
    
    第二个作用: 配合sed命令使用时,可以实现后项引用前项
    echo "123456"|sed -r 's#([0-9]+)#<\1>#g'
    <123456>
    echo "1234567890"|sed -r 's#([0-9])#<\1>#g'
    echo "789"|sed -r 's#(.)(.)(.)#<\1><\2><\3>#g'
    <7><8><9>
    说明: 后项引用前项只能引用1-9个小括号
    
    解锁: 批量创建用户 (密码是随机密码)
    [root@oldboyedu oldboy]# seq -w 10|sed -r 's#(.*)#useradd oldboy\1;echo 123456|passwd --stdin oldboy\1#g'
    useradd oldboy01;echo 123456|passwd --stdin oldboy01
    useradd oldboy02;echo 123456|passwd --stdin oldboy02
    useradd oldboy03;echo 123456|passwd --stdin oldboy03
    useradd oldboy04;echo 123456|passwd --stdin oldboy04
    useradd oldboy05;echo 123456|passwd --stdin oldboy05
    useradd oldboy06;echo 123456|passwd --stdin oldboy06
    useradd oldboy07;echo 123456|passwd --stdin oldboy07
    useradd oldboy08;echo 123456|passwd --stdin oldboy08
    useradd oldboy09;echo 123456|passwd --stdin oldboy09
    useradd oldboy10;echo 123456|passwd --stdin oldboy10
    [root@oldboyedu oldboy]# seq -w 10|sed -r 's#(.*)#useradd oldboy\1;echo 123456|passwd --stdin oldboy\1#g'|bash
    Changing password for user oldboy01.
    passwd: all authentication tokens updated successfully.
    Changing password for user oldboy02.
    passwd: all authentication tokens updated successfully.
    Changing password for user oldboy03.
    passwd: all authentication tokens updated successfully.
    Changing password for user oldboy04.
    passwd: all authentication tokens updated successfully.
    Changing password for user oldboy05.
    passwd: all authentication tokens updated successfully.
    Changing password for user oldboy06.
    passwd: all authentication tokens updated successfully.
    Changing password for user oldboy07.
    passwd: all authentication tokens updated successfully.
    Changing password for user oldboy08.
    passwd: all authentication tokens updated successfully.
    Changing password for user oldboy09.
    passwd: all authentication tokens updated successfully.
    Changing password for user oldboy10.
    passwd: all authentication tokens updated successfully.

    问题: 
    echo "1234567890"|sed -r 's#(.)(.)(.)(.)(.)(.)(.)(.)(.)(.)#<\1><\2><\3><\4><\5><\6><\7><\8><\9><(\10)>#g'
    <1><2><3><4><5><6><7><8><9><(10)>

4.{} 匹配前一个字符连续出现指定的次数

{n,m}  --- 匹配前一个字符连续出现至少n次 最多m次
       [root@oldboyedu oldboy]# grep -E "0{2,4}" oldboy.txt 
       my qq num is 49000448.
       not 4900000448.
       [root@oldboyedu oldboy]# grep -E "0{2,4}" oldboy.txt -o
       000
       0000
       [root@oldboyedu oldboy]# grep -E "0{1,3}" oldboy.txt -o
       0
       000
       000
       00
       [root@oldboyedu oldboy]# grep -E "0{1,3}" oldboy.txt
       our site is 0 http://www.etiantian.org
       my qq num is 49000448.
       not 4900000448.
{n}    --- 匹配前一个字符连续出现正好n次
       [root@oldboyedu oldboy]# grep -E "0{3}" oldboy.txt
       my qq num is 49000448.
       not 4900000448.
       [root@oldboyedu oldboy]# grep -E "0{2}" oldboy.txt
       my qq num is 49000448.
       not 4900000448.
{n,}   --- 匹配前一个字符连续出现最少n次, 最多不限
{,m}   --- 匹配前一个字符连续出现最少0次, 最多是m次
       [root@oldboyedu oldboy]# grep -E "0{3,}" oldboy.txt 
       my qq num is 49000448.
       not 4900000448.
       [root@oldboyedu oldboy]# grep -E "0{,3}" 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 0 http://www.etiantian.org
       my qq num is 49000448.
       
       not 4900000448.
       my god ,i am not oldbey,but OLDBOY!

5.? --- 匹配前一个字符连续出现0次或者1次

      总结: * + {} ?
      [root@oldboyedu oldboy]# egrep "o*" test02.txt 
      gd
      god
      good
      goood
      gooood
      [root@oldboyedu oldboy]# egrep "o+" test02.txt 
      god
      good
      goood
      gooood
      [root@oldboyedu oldboy]# egrep "o?" test02.txt 
      gd
      god
      good
      goood
      gooood
      [root@oldboyedu oldboy]# egrep "o?" test02.txt -o
      o
      o
      o
      o
      o
      o
      o
      o
      o
      o

总结:

通配符号: 匹配文件名称信息
正则符号: 匹配文件内容信息