Many common commands in Linux are required to master, here will share Linux entry often used basic commands, I hope to help you learn!!
Before we get started, I’d like to share with you a video about Linux
The video explains the origin and development of Linux, the installation and configuration of CentOS, a common Linux system used by enterprises.
This section describes the ten types of Linux commands and provides examples. Web applications developed with JAVA.
Build Web application running environment in Linux :JDK,MySQL,Tomcat installation, configuration, log view, etc.
Deploy the Web application as a WAR. Video learning can meet the actual combat requirements in the enterprise.
Watch online: www.bilibili.com/video/BV1Li.
Data download: www.bjpowernode.com/javavideo/1…
File directory instruction
The PWD command
Basic syntax: PWD
Displays the path of the current directory
Practical case:
The ls command
Basic syntax :ls [option] [directory or file]
Commonly used options
- A: Displays all files and directories in the current directory, including hidden ones.
- L: Displays information in a list, equivalent to LL
Practical case:
List all files and directories in the current directory:
The CD instruction
Basic syntax: CD [parameter]
Switch to a specified directory
Commonly used parameters
Absolute paths (directories starting with /) and relative paths (directories starting with a directory name, starting from the current directory)
CD ~ or CD: go to your home directory
cd .. Go back to the directory one level above the current directory
Practical case:
The mkdir command
Basic syntax:
Mkdir [option] Directory to create
Commonly used options
P: Create a multi-level directory
Practical case:
Rmdir commands
Basic syntax:
Rmdir directory
Delete an empty directory
Practical case:
Touch the instructions
Basic syntax:
Touch File name list
Create one or more empty files
Practical case:
The cp command
Basic syntax:
Cp [option] source dest
Common options:
R: Recursively copy the entire folder
Practical case:
The rm command
Basic syntax:
Rm [option] File or directory to be deleted
Common options:
- R: Delete the entire folder recursively
- F: Forcible deletion is not prompted
Practical case:
The mv command
Basic syntax:
Mv oldNameFile newNameFile
Mv /temp/ moveFile /targetFolder
Practical case:
The cat command
Basic syntax:
Cat [option] File name to view
Commonly used options
N: Displays the line number
Practical case:
More instructions
Basic syntax:
More Indicates the file name to view
Function description: The more command is a text filter based on the VI editor, which displays the content of the text file by page in a full-screen way.
Shortcut:
Practical case:
Less instruction
Basic syntax:
Less Indicates the name of the file to be queried
Less command is used to view file content in split screen. Its function is similar to more command, but more powerful than more command. It supports various display terminals. The less command does not load the entire file at one time, but loads the content according to the display requirements, which is efficient for displaying large files.
Shortcut:
Practical case:
The head instructions
Basic syntax:
- Head file (default view the first 10 lines of the file)
- Head -n 5 file (function description: View the first 5 lines of the file, 5 can be any number of lines)
Practical case:
Tail instruction
Basic syntax:
- Tail file (View the last 10 lines of the file by default)
- Tail -n 5 File (Function description: View the last 5 lines of the file. 5 can be any number of lines.)
Practical case:
The echo command
Basic syntax:
Echo [options] [output content]
Output variable or constant content to console
Practical case:
> instructions
Basic syntax: View Instructions > Target file
Function description: overwrite the result in the previous view command to the target file, if the target file does not exist, then create a new one.
Practical case:
> > instructions
Basic syntax: View instructions >> target file
Add the result of the previous view command to the target file. If the target file does not exist, create a new one.
Practical case:
Time date instruction
The date order
Basic syntax:
-
Date (display current time)
-
Date +%Y
-
Date +%m
-
Date +%d
-
Date “+%Y-%m-%d %H:% m :%S”
-
Date -s String time (set date)
Practical case:
CAL instruction
Basic syntax:
CAL [option] (No option, display calendar of this month)
Practical case:
Search search instruction
The find command
The find command recursively traverses the subdirectories from the specified directory and displays the files or directories that meet the conditions on the terminal.
Basic syntax:
Find [option]
Options:
- Name: Search by name. Wildcard characters are supported.
- User: Search by user name
- Size: Search by file size
Practical case:
The locate command
Basic syntax:
Locate Specifies the name of the file to search for
The Locate directive can quickly locate file paths throughout the system. The Locate directive quickly locates a given file using the LOCATE database of all file names and paths established in the system. The Locate command does not need to traverse the entire file system, resulting in faster queries. To ensure the accuracy of query results, administrators must periodically update locate time.
Practical case:
The grep command
Basic syntax:
Grep [option] The content of the source file to search for
Common options:
- N: Displays the matching line and its number
- I: Ignore case
Description: grep filters lookup, pipeline operators, “|”, said it would before the processing of a command output is passed to the back of the order processing results.
Practical case:
Compression and decompression instructions
Gzip command
Basic syntax: Gzip file
Function Description: Compress a file to a *. Gz file and store it in the directory where the original file resides. After the compression is successful, the original file will be deleted. Used to compress a single file.
Practical case:
Gunzip command
Basic syntax: Gunzip file
Function Description: This command is used to decompress files. After the decompression is successful, the files are stored in the directory where the original compressed files are located, and the original compressed files are deleted.
Practical case:
Zip instruction
Basic syntax:
Zip [option] xxx. zip The content to be compressed
Function description: Compress a specified file or directory into XXX. Zip file, used to compress all file structures.
R: indicates recursive compression, that is, compressed directories
Practical case:
Unzip the instructions
Basic syntax:
Unzip [option] xxx.zip
Common options: d Directory: Specifies the directory for storing decompressed files
Practical case:
The tar command
Basic syntax:
Tar [option] xxx.tar. gz [packaged content]
Function description: Package or decompress files
Options:
- C: Generate the.tar.gz package file
- V: Displays detailed information
- F: Specifies the compressed file name
- Z: Package and compress
- X: Decompress the.tar.gz file
- C: Specify the directory to decompress
Practical case:
Group management instruction
Basic introduction to Linux group:
In Linux, each user must belong to a group. The user group can be changed.
In Linux, each file has an owner, a group to which it belongs, other groups, and you can change the group.
The owner of the file/directory
By default, the owner belongs to the same group that the file belongs to.
View file owner and group directives
Basic syntax:
Ls - AHl File name
(a-all,h-human,l-list)
Practical case:
Modify the file owner directive
Basic syntax:
Chown new owner file name
Chown newowner:newgroup file Changes both the owner and all groups of the user
R Recursively applies to all subfiles or directories if it is a directory
Modify the file owner to the specified user.
Practical case:
Modify the group command of a file
Basic syntax:
CHGRP Indicates the name of the new group
R Recursively applies to all subfiles or directories if it is a directory
Change the group where a file resides to a specified group
Practical case:
Permission management instruction
Basic Introduction to Permissions
All permissions mentioned here are file and directory permissions. In Linux, each file and directory has its own access rights, which can be viewed in the file list.
RWX permission details
RWX applies to files
-
[r] stands for read: to read, to view
-
[w] indicates Write: A file can be modified but cannot be deleted. A file can be deleted only when you have the write permission on the directory where the file resides.
-
[x] indicates execute: can be executed
RWX applies to directories
-
[r] stands for read: the directory can be read
-
[w] indicates Write: you can create, delete, and rename directories in a directory
-
[x] indicates execute: The directory can be accessed
RWX is represented by numbers
R =4(2 ^ 2),w=2(2 ^ ¹),x=1(2º)
Permission management instruction
Command to modify file/directory permissions chmod
The first method is to change the permission through r, W, or X
-
Chmod u= RWX,g=rx,o=x File directory name
-
Chmod o+w Specifies the name of the file directory
-
Chmod a-x Specifies the name of the file directory
Note: u, G, O, and A respectively represent the file owner, the user in the file owning group, the user in other groups, and all users. =, +, and – respectively indicate setting permission, adding permission, and removing permission
The second way: change permission through numbers
Chmod Directory name of a group of three digital files
R =4 w=2 x=1 RWX =4+2+1=7
Practical case:
