The regular expression of the formation of the Great God of Linux (grep,sed)

The regular expression grep command in the form of the great God of Linux

Parameters:

• -A followed by a number representing after, indicating that the row's subsequent n rows are also listed
• -B followed by a number, representing the Befer, indicating that the row is listed in front n rows

|-n-A3-B2--color=‘eth‘

1. Find a specific string

$ 

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 8  I can‘t finish the test.^M 9  Oh! The soup taste good.^M10  motorcycle is cheap than car.11  This window is clear.12  the symbol ‘*‘ is represented as start.13  Oh!     My god!14  The gd software is a library for drafting programs.^M15  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.19  goooooogle yes!20  go! go! Let‘s go.21  # I am VBird

$ ‘the‘

8:i can ' t finish the Test.^m
12:the symbol ' * ' is represented as start.
15:you is the best was mean you are the No. 1.
16:the World was the same with "glad".
18:google is the best tools for search keyword.

2. use brackets to find the set character

$ ‘t[ae]st‘

8:i can ' t finish the Test.^m
9:oh! The Soup taste good.^m
Find a sentence that contains tast or test characters

$ ‘[^g]oo‘

2:apple is my favorite food.
3:football game isn't use feet only.
18:google is the best tools for search keyword.
19:goooooogle yes!
^ Reverse selection, that is, the non-meaning of OO is not the letter of the front of G

$ ‘[^a-z]oo‘

3:football game isn't use feet only.
OO Front is non-lowercase

3. beginning and end of line character ^$

$ grep -n ‘^[a-z]‘ regular_express.txt


2:apple is my favorite food.
4:this dress doesn ' t fit me.
10:motorcycle is cheap than car.
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.
^ Put on the outside to indicate the beginning of the line, indicating that the row starts with a lowercase letter

$ ‘^[^a-zA-Z]‘

1: "Open Source" is a good mechanism to develop programs.
21:# I am Vbird
Lines that don't start with a letter

$ ‘\.$‘

1: "Open Source" is a good mechanism to develop programs.
2:apple is my favorite food.
3:football game isn't use feet only.
4:this dress doesn ' t fit me.
10:motorcycle is cheap than car.
11:this window is clear.
12:the symbol ' * ' is represented as start.
15:you is the best was mean you are the No. 1.
16:the World was the same with "glad".
17:i like dog.
18:google is the best tools for search keyword.
20:go! Go! Let ' s go.
$ represents the end of the line, which represents the line ending with '. ', where ' \ ' is an escape character

grep‘^$‘grep  ‘^#‘

# Log all kernel messages to the console.
# Logging Much else clutters up the screen.
#kern. */dev/console
# Log anything (except mail) of level info or higher.
# Don ' t log private authentication messages!
# The Authpriv file has restricted access.
# Log All of the mail messages in one place.
# Log Cron Stuff
# Everybody gets emergency messages
# Save News errors of level crit and higher in a special file.
# Save Boot messages also to Boot.log
Select a non-empty line, and then select the text that begins with #

4. any one. and repeated *


$ grep -n ‘g..d‘ regular_express.txt


1: "Open Source" is a good mechanism to develop programs.
9:oh! The Soup taste good.^m
16:the World was the same with "glad".
' G.. d ' means that there are two consecutive arbitrary characters in the middle of G and D that can match

$ ‘goo*g‘

18:google is the best tools for search keyword.
19:goooooogle yes!
' Goo*g ' before an o must have, after an ' O * ' represents one or more, so for at least one O

grep -n g.*g

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.
Lines representing the end of G starting with G

$ grep -n ‘[0-9][0-9]*‘ regular_express.txt

5:however, this dress was about $3183 dollars.^m
15:you is the best was mean you are the No. 1.
Represents a line that starts with a number, followed by 0 to any number

5. Limit the range of consecutive re characters {}


$ grep -n ‘o\{2\}‘ regular_express.txt


1: "Open Source" is a good mechanism to develop programs.
2:apple is my favorite food.
3:football game isn't use feet only.
9:oh! The Soup taste good.^m
18:google is the best tools for search keyword.
19:goooooogle yes!
Represents a row that contains two ' o '

$ ‘go\{2,\}g‘ regular_express.txt

18:google is the best tools for search keyword.
19:goooooogle yes!
The middle of G and G contains more than two O

SED tools

Parameters:

• -N Quiet mode, listing only specially processed rows
• -I directly modifies the contents of the file, not the screen output
• -e sed action edit directly in command line mode
• -F SED action written in a file
• -R Extended Regular syntax

function parameters;

• A new
• C Replace
• D Delete
• I insert
• P Printing

• s replacement (and C for different viewing exercises)

  1. Add/Remove in behavioral units

$ ‘2,5d‘

1 root:x:0:0:root:/root:/bin/bash 6  sync:x:5:0:sync:/sbin:/bin/sync 7  shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown 8  halt:x:7:0:halt:/sbin:/sbin/halt 9  mail:x:8:12:mail:/var/spool/mail:/sbin/nologin PS:表示删除第2-5行

$ ‘2a Drink tea or .....\ > drink bear ?‘

1 Root:x:0:0:root:/root:/bin/bash
2 Bin:x:1:1:bin:/bin:/sbin/nologin
Drink tea or .....
Drink bear?
3 Daemon:x:2:2:daemon:/sbin:/sbin/nologin
4 Adm:x:3:4:adm:/var/adm:/sbin/nologin
5 Lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
PS: Add the following string after the second line, with ' \ ' to indicate a new line increment

2. The function of replacing the display in the behavior unit

$ nl /etc/passwd | sed ‘2,5c No 2-5 number‘


1 Root:x:0:0:root:/root:/bin/bash
No 2-5 Number
6 Sync:x:5:0:sync:/sbin:/bin/sync
7 Shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
PS: Replace 2-5 lines with ' No 2-5 number '

$ ‘2,5p‘

2 bin:x:1:1:bin:/bin:/sbin/nologin 3  daemon:x:2:2:daemon:/sbin:/sbin/nologin 4  adm:x:3:4:adm:/var/adm:/sbin/nologin 5  lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin PS：注意这里 ‘-n‘ 安静模式，只列出特殊处理的行

$ /sbin/ifconfig eth1

eth1 Link encap:ethernet HWaddr 6c:ae:8b:21:98:9b
inet addr:10.209.102.43 bcast:10.209.102.127 mask:255.255.255.128
Up broadcast RUNNING multicast mtu:1500 metric:1
RX packets:47103902950 errors:0 dropped:7743 overruns:7743 frame:0
TX packets:11073405019 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:59771891524541 (54.3 TiB) TX bytes:810933823454 (755.2 GiB)

$ /sbin/ifconfig eth1  ‘inet addr‘

     inet addr:10.209.102.43  Bcast:10.209.102.127  Mask:255.255.255.128

$ /sbin/ifconfig eth1  ‘inet addr‘‘s/^.*addr://g‘

10.209.102.43 bcast:10.209.102.127 mask:255.255.255.128
PS: "sed ' s/to replace character/new character/g '"

$ /sbin/ifconfig eth1  ‘inet addr‘‘s/^.*addr://g‘‘s/Bcast.*//g‘

10.209.102.43
PS: In fact, it is equivalent to Hostname-i

$ ‘MAN‘‘s/#.*$//g‘‘/^$/d‘

Manpath/usr/share/man
Manpath/usr/man
Manpath/usr/local/share/man
Manpath/usr/local/man
Manpath/usr/x11r6/man
Manpath_map/bin/usr/share/man
Manpath_map/sbin/usr/share/man
Manpath_map/usr/bin/usr/share/man
Manpath_map/usr/sbin/usr/share/man
PS: First select the line containing ' man ', then replace ' # ', that is, the comment, and then delete the blank line, note that the last empty line is written in a pair of '//'

• Directly modify the file (dangerous operation)

$ ‘s/\.$/\!/g‘

PS: Directly to the original file in the '. ' Replace all endings with '! ’

$ ‘$a # This is a tese‘

PS: Add a sentence to the last line of the article

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

The regular expression of the formation of the Great God of Linux (grep,sed)