Linux basics-3day-Linux document operation command-(cat/more/less/head/tail)

Linu X document operation command - ( CAT / More / less / head / tail )

1. The cat command

Description: View file content; file creation; file merge. It is often used to display the content of a file, or connect several files to display, or read the content from standard input and display it. It is often used in conjunction with the redirection symbol.

Usage: cat [parameter options] [file name] 

parameter:

parameter	significance
-b	Display line number, blank cell does not display
-n	Display the line number, also display blank cells
-E	Display $ at the end of each line
-s	If there are more than two consecutive blank lines, replace them with one blank line
-T	--show-tabs displays tab characters as ^I

Eg1 :

[root@test ~]#cat -n ping.sh test.txt #Add a line number to display the contents of two files 
[root@test ~]#cat ping.sh test.txt >test1.txt #Merge two files into one 
[root@test ~]#cat> test2.txt #Create file text2.txt and write

2. More command

Description: View the content of the file by page, view the next page by space bar, and q to exit.

Usage: more [parameter options] [file name]

parameter:

parameter	significance
+n	Display from line n
-n	Define the screen size as n lines
-c/-p	Clear the screen from the top, and page the file by clearing the window instead of scrolling
-s	Multiple blank lines will be displayed as one line
-u	Remove the underscore from the content of the file
+/pattern	Search for the pattern before each file is displayed, and then start displaying after the first two lines of the string

Common operation commands:

action	significance
Enter	Down n lines, need to be defined, the default is 1 line
Ctrl+F	Scroll down one screen
Ctrl+B	Scroll up one screen
=	Output current line number
v	Call vi edit
：f	Display current file name and current line number
!command	Execute shell commands
q	drop out

3. Less command

Description: View file content in pages.

Usage: less [parameter options] [file name]

parameter:

parameter	Features
-e	After the file is displayed, it will exit automatically
-f	Force opening of special files, such as directories, binary files, etc.
-g	Only mark the last searched keyword
-i	Ignore case when searching
-m	Show the percentage of commands like more
-o <file name>	Save the content output by less in the specified file
-Q	Not applicable warning sound
-s	Show continuous empty rows
-S	When the line is too long, discard the extra part
-x<number>	Display the "tab" key value as a number space
/String	Search string down
?String	Search string up

Common operations:

action	Features
n	Repeat the previous search
N	Repeat the previous search in reverse
b	Page backward
d	Page forward
h	Show help interface
q	Exit the less command
u	Scroll forward half a page
and	Scroll forward one line
Space	Scroll one line
Carriage return	Scroll one page
pgup	Page up
pgdown	Page down

4. The head command

Description: View the content of the file header, the first 10 lines are displayed by default

Usage: head [parameter options] [file name]

parameter:

-q	Hide file name
-v	Show file name
-n<number of lines>	Display line number
-c<byte>	Display the number of bytes

Eg1:

[root@test ~]# head -n test #Display the first 20 lines of the file test

5. Tail command

描述：查看文件尾部内容，默认显示10行。

用法：tail  [参数选项] [文件名程]

参数：

-n	显示文件末尾n行内容
-f	动态显示文件内容，常用于查看实时日志信息
--pid=PID	与-f合用,表示在进程ID,PID死掉之后结束.

Eg:

[root@test ~]# tail -n 20 test     #显示test文件后20行

个人公众号：