项目七 熟练使用Vim程序编辑器与shell

#职业能力目标和要求
1,学会使用vim编辑器2,了解shell的强大功能shell命令解释过程。
3,学会使用重定向管道方法4,掌握正则表达式使用方法

7.1 熟悉使用vim编辑器

7.1.1 启动与退出vim

1,vim命令格式vim +创建/编辑文件

2,vim编辑环境

3,编译时的命令

:w			#保存
:w filename	#另存为filename
:wq!		#保存退出
:x			#保存退出
:wq!		#注:以filename文件名保存后退出
:q!			#不保存退出

7.1.2 熟悉掌握vim的工作模式.

1,编辑模式

  • 首先进来的就是该模式
  • 编辑行是_表示;不在编辑行~表示。
  • 如果左下角是[New File],则表示该文件是新建文件。
  • 模式下左下角什么都没有。

2,插入模式

3,命令模式

  • (如果是插入模式,先按”Esc” 键进人编辑模式)在编辑模式下,按“:”键即可进入命令模式;此时左下角有”:“提示符,可以输入命令;执行自动回到编辑模式。
  • 若改变主意,按退格键全删即可回到编辑模式。

7.1.3 使用vim命令

1,编辑模式

image.png

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2,命令模式

image.png

7.2 熟悉掌握shell环境变量

shell是用与操作写入内核之间的接口,起着交互作用;shell支持具有字符串值的变量

1,变量定义引用

变量赋值格式name=string
#name变量名,=是赋值符号string是值

2,shell变量的作用域

shell变量分为局部变量和全局变量。

#举例:
#定义两个变量
[root@localhost ~]# var1=Linux
[root@localhost ~]# var2=unix
#用export命令改成全局变量
[root@localhost ~]# export var2
#显示引用的变量
[root@localhost ~]# echo $var1 
Linux
[root@localhost ~]# echo $var2
unix
#显示当前shell的pid
[root@localhost ~]# echo $$
2972
#调用子shell
[root@localhost ~]# bash
#查看子shell的pid
[root@localhost ~]# echo $$
66239
#引用子shell的变量,可以看出var1,没有显示,说明var1为局部变量
[root@localhost ~]# echo $var1

[root@localhost ~]# echo $var2
unix
#退出子shell,并重新引用变量
[root@localhost ~]# exit
exit
[root@localhost ~]# echo $$
2972
[root@localhost ~]# echo $var1 
Linux
[root@localhost ~]# echo $var2
unix

3,环境变量

image.png

  • 不加参数set命令,可以显示当前所有环境变量的设置

  • 环境变量前加$符号,表示引用

  • 修改环境变量时

    #例如:将一个路径/tmp加到PATH变量前
    [root@localhost ~]# PATH=/tmp:$PATH
    
  • unset命令:将环境变量重新设置为系统默认值。

4,命令运行的判读依据:;,&&,||

  • cmd;cmd(不考虑命令相关性的连续命令执行
  • $?(命令回传值)与”&&“或“||”

image.png

**注意:**两个&之间是没有空格的,“1”则是按“Shift+” 组合键的结果

#例题1:如果不管/tmp/abc存在与否,都要创建/tmp/abc/hehe文件,怎么办呢?
[root@localhost ~]# ls /tmp/abc || mkdir /tmp/abc && touch /tmp/abc/hehe

#例题2:以ls测试/tmp/bobbying是否存在:若存在,则显示“exist"; 若不存在,则显示“not exist”
[root@localhost ~]# ls /tmp/bobbying && echo "exist" || echo "not exist"

5,工作环境设置文件

环境变量文件有两种

注:只有在特定的情况下才读取profile文件,确切地说是在用户登录的时候读取。当运行shell 脚本以后,就无须再读profile文件。

7.3 熟悉掌握正则表达法

正则表示法就是处理字符串方法,它以“行”为单位来进行字符串处理

7.3.1 掌握grep的高级使用

格式: grep [-A] [-B] [–color=auto] ‘查找字符串filename

  • -A:后面可加数字,为after的意思,除了列出该行外,后续的n行也列出来。
  • -B:后面可加数字,为befor的意思,除了列出该行外,前面的n行也列出来。
  • coloreauto.可将搏寻出的正确数掘用特殊颜色标记
#例1:用demsg列出核心信息,再以grep找出内含IPv6的那行
[root@localhost ~]# dmesg | grep 'IPv6'
[    6.769531] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
[    6.778049] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
[    6.778875] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
[   11.978750] IPv6: ADDRCONF(NETDEV_UP): virbr0: link is not ready
[   87.408060] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
[   87.409345] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
[  117.501771] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
[  117.503142] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
[  128.247837] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
[  128.249073] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
[51085.622677] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
[51085.626092] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
#例2:承上賄要将本取到的关键字显色,日加上行号(-n)来表示
[root@localhost ~]# dmesg | grep -n --color=auto 'IPv6'
1831:[    6.769531] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
1833:[    6.778049] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
1834:[    6.778875] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
1846:[   11.978750] IPv6: ADDRCONF(NETDEV_UP): virbr0: link is not ready
1852:[   87.408060] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
1854:[   87.409345] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
1855:[  117.501771] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
1857:[  117.503142] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
1858:[  128.247837] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
1860:[  128.249073] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
1863:[51085.622677] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
1865:[51085.626092] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
#例3:
[root@localhost ~]# dmesg | grep -n -A1 -B1 --color=auto 'IPv6'
1830-[    6.559585] NET: Registered protocol family 40
1831:[    6.769531] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
1832-[    6.773124] e1000: ens33 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None
1833:[    6.778049] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
1834:[    6.778875] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
1835-[   11.501269] ip6_tables: (C) 2000-2006 Netfilter Core Team
--
1845-[   11.978664] virbr0: port 1(virbr0-nic) entered listening state
1846:[   11.978750] IPv6: ADDRCONF(NETDEV_UP): virbr0: link is not ready
1847-[   12.022448] virbr0: port 1(virbr0-nic) entered disabled state
--
1851-[   33.946364] TCP: lp registered
1852:[   87.408060] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
1853-[   87.408574] e1000: ens33 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None
1854:[   87.409345] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
1855:[  117.501771] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
1856-[  117.502326] e1000: ens33 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None
1857:[  117.503142] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
1858:[  128.247837] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
1859-[  128.248338] e1000: ens33 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None
1860:[  128.249073] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready
1861-[22294.767165] e1000: ens33 NIC Link is Down
1862-[22304.806220] e1000: ens33 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None
1863:[51085.622677] IPv6: ADDRCONF(NETDEV_UP): ens33: link is not ready
1864-[51085.625314] e1000: ens33 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None
1865:[51085.626092] IPv6: ADDRCONF(NETDEV_CHANGE): ens33: link becomes ready

7.3.2 练习基础正则表达式

在root下编写sample.txt测试文件

"Open Source" is a good mechanism to develop programs.
apple is my favorite food.
Football game is not use feet only.
this dress doesn't fit me.
However, this dress is about $ 3183 dollars.^M
GNU is free air not free beer.^M
Her hair is very beauty.^M
I can't finish the test.^M
Oh! The soup taste good.^M
motorcycle is cheap thancar.
This window is clear.
the symbol '*' is represented as start.
Oh!     My god!
The gd software is a library for drafting programs.^M
You are the best is mean you are the no. 1.
The world <Happy> is the same with "glad".
I like dog.
google is the best tools for search keyword.
goooooogle yes!
go! go! Let's go.
#I am Bo

1,查找特定字符串

#查找“the”字符串
[root@localhost ~]# grep -n 'the' /root/sample.txt 
8:I can't finish the test.^M
12:the symbol '*' is represented as start.
15:You are the best is mean you are the no. 1.
16:The world <Happy> is the same with "glad".
18:google is the best tools for search keyword.
#反向选择(就是除去the字符串)
[root@localhost ~]# grep -vn 'the' /root/sample.txt 
1:"Open Source" is a good mechanism to develop programs.
2:apple is my favorite food.
3:Football game is not use feet only.
4:this dress doesn't fit me.
5:However, this dress is about $ 3183 dollars.^M
6:GNU is free air not free beer.^M
7:Her hair is very beauty.^M
9:Oh! The soup taste good.^M
10:motorcycle is cheap thancar.
11:This window is clear.
13:Oh!	My god!
14:The gd software is a library for drafting programs.^M
17:I like dog.
19:goooooogle yes!
20:go! go! Let's go.
21:#I am Bo
[root@localhost ~]# grep -in 'the' /root/sample.txt 
8:I can't finish the test.^M
9:Oh! The soup taste good.^M
12:the symbol '*' is represented as start.
14:The gd software is a library for drafting programs.^M
15:You are the best is mean you are the no. 1.
16:The world <Happy> is the same with "glad".
18:google is the best tools for search keyword.

2,利用中括号[]]来搜寻集合字符

#如何查找含“test”,“teste”?
[root@localhost ~]# grep -n 't[ae]st' /root/sample.txt 
8:I can't finish the test.^M
9:Oh! The soup taste good.^M
#[]里面无论几个字符,都只代表一个字符。
#如何查找含“oo”的字符?
[root@localhost ~]# grep -n 'oo' /root/sample.txt 
1:"Open Source" is a good mechanism to develop programs.
2:apple is my favorite food.
3:Football game is not use feet only.
9:Oh! The soup taste good.^M
18:google is the best tools for search keyword.
19:goooooogle yes!

#例如大写英文/小写英文/数字等,可以用[a-z][A-Z][0-9]
#查询数字的行
[root@localhost ~]# grep -n '[0-9]' /root/sample.txt 
5:However, this dress is about $ 3183 dollars.^M
12:the symbol '*' is represented as start.

#[:lower:]表示a-z的意思。
[root@localhost ~]# grep -n '[^[:lower:]]oo' /root/sample.txt 
3:Football game is not use feet only.

3,首行与行尾字节^$

#显示"the"只在行首
[root@localhost ~]# grep -n '^the' /root/sample.txt 
12:the symbol '*' is represented as start.

#显示以小写开头
[root@localhost ~]# grep -n '^[a-z]' /root/sample.txt 
2:apple is my favorite food.
4:this dress doesn't fit me.
10:motorcycle is cheap thancar.
12:the symbol '*' is represented as start.
18:google is the best tools for search keyword.
19:goooooogle yes!
20:go! go! Let's go.

#显示不要字母
[root@localhost ~]# grep -n '^[^a-zA-Z]' /root/sample.txt 
1:"Open Source" is a good mechanism to develop programs.
21:#I am Bo

^符号在[]之内表示“反向选择”,在[]之外表示定位在行首

#找出行尾结束为小数点的行(用跳转字节
[root@localhost ~]# grep -n '^[^a-zA-Z]' /root/sample.txt 
1:"Open Source" is a good mechanism to develop programs.
21:#I am Bo
[root@localhost ~]# grep -n '.$' /root/sample.txt 
1:"Open Source" is a good mechanism to develop programs.
2:apple is my favorite food.
3:Football game is not use feet only.
4:this dress doesn't fit me.
10:motorcycle is cheap thancar.
11:This window is clear.
12:the symbol '*' is represented as start.
15:You are the best is mean you are the no. 1.
16:The world <Happy> is the same with "glad".
17:I like dog.
18:google is the best tools for search keyword.
20:go! go! Let's go.

#利用cat显示不打印字符,行尾显示“$”
[root@localhost ~]# cat -An /root/sample.txt | head -n 10 |tail -n 6
     5	However, this dress is about $ 3183 dollars.^M$
     6	GNU is free air not free beer.^M$
     7	Her hair is very beauty.^M$
     8	I can't finish the test.^M$
     9	Oh! The soup taste good.^M$
    10	motorcycle is cheap thancar.$

#不要空行的打印(-v '^$')
[root@localhost ~]# grep -v '^$' /etc/rsyslog.conf |grep -v '^$'

4,任意一个字符“.“与重复字节”*“

  • “*”:代表0个或多个字符。
  • “.”:代表绝对有一个任意字符。
#找“g??d”的字符串
root@localhost ~]# grep -n 'g..d' /root/sample.txt 
1:"Open Source" is a good mechanism to develop programs.
9:Oh! The soup taste good.^M
16:The world <Happy> is the same with "glad".

#查找两个“oo”以上的字符串(两个oo以后可以是0个或无数个)
[root@localhost ~]# grep -n 'ooo*' /root/sample.txt 
1:"Open Source" is a good mechanism to develop programs.
2:apple is my favorite food.
3:Football game is not use feet only.
9:Oh! The soup taste good.^M
18:google is the best tools for search keyword.
19:goooooogle yes!

#开头查找开头结尾都是g的字符串,之间有无字节皆可
[root@localhost ~]# grep -n 'g*g' /root/sample.txt 
1:"Open Source" is a good mechanism to develop programs.
3:Football game is not use feet only.
9:Oh! The soup taste good.^M
13:Oh!	My god!
14:The gd software is a library for drafting programs.^M
16:The world <Happy> is the same with "glad".
17:I like dog.
18:google is the best tools for search keyword.
19:goooooogle yes!
20:go! go! Let's go.
#改结果问题我们重新定义一下
[root@localhost ~]# grep -n 'g.*g' /root/sample.txt 
1:"Open Source" is a good mechanism to develop programs.
14:The gd software is a library for drafting programs.^M
18:google is the best tools for search keyword.
19:goooooogle yes!
20:go! go! Let's go.

#“.*”代表任意字符;RE:正则表达式

#显示仅有数字,用RE法
[root@localhost ~]# grep -n '[0-9][0-9]*' /root/sample.txt 
5:However, this dress is about $ 3183 dollars.^M
15:You are the best is mean you are the no. 1.

5,限定连续RE字符范围

#查找含有两个o的字符串的行
[root@localhost ~]# grep -n 'o{2}' /root/sample.txt 
1:"Open Source" is a good mechanism to develop programs.
2:apple is my favorite food.
3:Football game is not use feet only.
9:Oh! The soup taste good.^M
18:google is the best tools for search keyword.
19:goooooogle yes!
#再假设要找后面接2~5个o,然后再接一个g的字符串
[root@localhost ~]# grep -n 'go{2,5}g' /root/sample.txt 
18:google is the best tools for search keyword.
#再假设查两个以上o的
[root@localhost ~]# grep -n 'go{2,}g' /root/sample.txt 
18:google is the best tools for search keyword.
19:goooooogle yes!

7.3.3 基础正则表达式的特殊字符汇总

image.png

7.4 掌握输入输出重定向管道命令的应用

7.4.1 使用重定向

1,重定向就是不用系统的标准,而进行重新指定

2,重定向分为输入重定向输出重定向和错误重定向

image.png

3,在执行命令前,命令解释程序会自动打开(如果文件不存在,则自动创建)且清空该文件(文中已存在的数据将被删除实际环境要慎重使用输入重定向。当执行完成时,命令解释程序正确关闭该文件,而命令在执行时并不知道它的输出已被重定向。

#1,将ls命令生成的/tmp目录的一个清单存到当前目录中的dir文件中
[root@localhost ~]# ls -l /tmp/ >dir
[root@localhost ~]# cat dir 
total 0
drwx------. 2 lzl  lzl  24 Jun 17  2022 ssh-J3eKGQfk53Ap
.....

#2,将ls命令生成的/etc目录的一个清单(就是显示出的内容)以追加的方式存到当前目录中。
[root@localhost ~]# ls -l /etc/ >>dir 
[root@localhost ~]# cat dir 
total 0
drwx------. 2 lzl  lzl  24 Jun 17  2022 ssh-J3eKGQfk53Ap
.....

#3,将命令myprogram的错误信息保存在当前目录下的err file文件中
[root@localhost ~]# myprogram &>err_file

#4,将命令myprogram的输出信息错误信息保存在当前目录下的output file 文件中。
[root@localhost ~]# myprogram &>output_file

#5,将命令ls的错误信息保存在当前目录下的err file文件中。
[root@localhost ~]# ls -l 2>err_file 
total 4669476
.....
#该命令并没有产生错误信息,但err file文件中的原文件内容会被清空

#6,Bash输人输出重定向可以通过使用下面选项设置为不覆盖已存在文件:
[root@localhost ~]# set -o noclobber
#这个选项仅用于当前命令解释程序输人输出进行重定向,而其他程序仍可能覆盖已存

#7,/dev/null设备(相当于垃圾桶)
#典型用法是丢弃从find或grep等命令送来的错误信息:
[root@localhost ~]# grep delegate /etc/* 2>/dev/null 
/etc/sudoers:## of related commands, which can then be delegated out to particular

**4,wc命令:**用来计算数字,可以计算文件的byte数,字数或是列数,若不指定文件名称,或是所给予的文件名为“_”,则wc指令会从标准输入设备读取数据

[root@localhost ~]# wc</etc/passwd
  43   87 2256

7.4.2 使用管道

1,定义:将这些命令前后衔接在一起,形成一个管道格式命令1|命令2|…|命令n

2,每条命令都是单独的进程运行,每条命令的输出作为下条命令的输入

3,由于命令的是从左到右顺序执行,所以管道线是单向的

#1,以长格式递归方式分屏显示/etc目录下的文件和目录列表
[root@localhost ~]# ls -Rl /etc | /more

#2,分屏显示文本文件/etc/passwd的内容
[root@localhost ~]# cat /etc/passwd | more 

#3,统计文本文件/et/passwd的行数、字数和字符数。期出
[root@localhost ~]# cat /etc/passwd | wc

#4,查看是否存在john用户账号
[root@localhost ~]# cat /etc/passwd |  grep john

#5,查看系统是否安装ssh软件包。
[root@localhost ~]# rpm -qa |grep ssh

#6,显示文本文件中的若干行。
[root@localhost ~]# tail -15 myfile |head -3

4,管道仅能操控命令的标准输出流。如果标准错误输出未重新定向,那么任何写入其中的信息都会在终端显示屏幕上显示。

[root@localhost ~]# who | grep root | wc -l
**。

```shell
#1,以长格式递归方式分屏显示/etc目录下的文件和目录列表
[root@localhost ~]# ls -Rl /etc | /more

#2,分屏显示文本文件/etc/passwd的内容
[root@localhost ~]# cat /etc/passwd | more 

#3,统计文本文件/et/passwd的行数、字数和字符数。期出
[root@localhost ~]# cat /etc/passwd | wc

#4,查看是否存在john用户账号
[root@localhost ~]# cat /etc/passwd |  grep john

#5,查看系统是否安装ssh软件包。
[root@localhost ~]# rpm -qa |grep ssh

#6,显示文本文件中的若干行。
[root@localhost ~]# tail -15 myfile |head -3

4,管道仅能操控命令的标准输出流。如果标准错误输出未重新定向,那么任何写入其中的信息都会在终端显示屏幕上显示。

[root@localhost ~]# who | grep root | wc -l

原文地址:https://blog.csdn.net/weixin_57789471/article/details/134630934

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