Linux Common commands

Change directory and view current directory commands

• CD: Go to User's home directory
• CD ~: Go to the user's home directory
• CD-: Returns the directory where it was before entering this directory
• Cd.. : Returns the parent directory (if the current directory is "/", then "/"; "..." after execution) Meaning for the parent directory)
• Cd..  /.. : Returns to the top level two directory
• PWD: Displays the current user's working directory location

Commands to display the contents of a file

• Cat: Used to display the entire contents of a specified file
• More: Displays the contents of the specified file in pagination
• Less: Displays the contents of the specified file in pagination, more powerful than more.
• Head: Used to display the first n rows of the file.
• Tail: Used to display the contents of the following n rows of a file.
• grep: Finds the contents of a file. Find a row containing some information, eg (Find rows in file day containing un): $ grep un day

Find File command:

• Find: Finding files within a specified range
• Locate: Search files faster than find
• Whereis: Used to locate Program files and provide the location of the binary executable file, source code files, and user pages of this file. You can use the-B option to find only binary executables.

User and version Information view

• Who: see who is logged in on the current system and which console they are working on.
• WHOAMI: Show your user name
• Uname: Displays version information for the current system
  • Uname-a: Displays all the useful information for the current system
  • Uname-r: Only the kernel version information is displayed

View commands

• Man: Getting Help for a command
• Whatis: Extract a simple introductory text from the user manual of a program to help you understand the general purpose of the program.
• Apropos: You can reverse a command by using the manual. For example, find the command that contains search in the user manual: Apropos search

commands for creating and deleting directories

• mkdir: You can create one or several directories at a time.
  • $ mkdir Document Picture # #新建两个目录
  • $ mkdir ~/picture/temp # #在主目录下新建名为temp的目录
  • $ mkdir-p ~/tempx/job # # If there is no tempx in the home directory, a subdirectory structure can be completely created with the-p option
• RmDir: Delete directory, only empty directory can be deleted

Move, copy, delete

• MV: Move files and directories (-I option to prompt for file coverage with the same name) and rename them while moving.
• CP: Copy files and directories (-I option to prompt for file overwrite with the same name)
• RM: Delete files and directories. Powerful than RmDir, you can recursively delete all files and directories under the directory.
  • Rm-i: prompt whether to delete
  • Rm-f: Automatic answer to prompt y
  • Rm-r: Recursively deletes all files and subdirectories under the directory.

Permissions for files and directories

• Change file permissions: chmod

chmod user Group +/-Permission file name

User groups: File owner (U), Group of documents (g), others (O) and All Persons (a)

Permissions: Read (r), write (W), execute (x)

chmod u+x days (increases the owner's execution rights for file days)

chmod a-x Days

chmod ug=rw,o=r Days (grants read/write permissions to the owner and the group, but only to other users.) ）

chmod o=u days (the permissions of others are set to the same as the permissions of the owner.) ）

PS: Remember that only the owner and root of the file have permission to modify the file.

Chown: The command used to change the properties of a file.

CHGRP: The command used to change the file group.

Chattr: Used to set files with non-delete and modify permissions.

Lsattr: Used to display hidden properties of a file or directory.

Create a file

• Touch: Create a new empty file

• VI: Create a new file in an edited way

Find command

Find: The command that finds the specified directory or file.

Whereis: Find the specified file source and binary files and manuals, etc.

Which: the location used to query for commands or aliases.

Locate: Quickly find the content specified in the system database .

Grep: Finds content that satisfies a condition within the specified file or standard output, standard input.

Commands to shut down and restart your computer

    

Shutdown:-R restarts immediately after shutdown

-K does not really shut down, but only sends a warning message to all users

-H does not restart after shutting down the machine

Poweroff: For power off and off

Init: Changing the operating level of the system

level 0 for shutting down the system

Level 1 for single user mode

Level 2 for Multi-user usage (but without network functionality)

Level 3 for Multi-user usage (with network full function)

Level 4 for user-defined usage patterns

Level 5 indicates the mode when entering x Windows

Level 6 to restart the system

Reboot: for computer restart

Halt: For shutting down a computer system

Compress and Package commands

Tar: Used to package multiple files or directories, but not compressed, and also unpacked with commands

Gzip: For file compression and decompression commands, the file name extension is end of . GZ .

Gunzip: Used to decompress the gzip compressed document.

BZIP2: Used to compress and decompress files or directories

Bzcat: Used to display the contents of a compressed file.

Compress/un Compress: Compression / decompression . Z File

Zcat: View Compressed file contents at the end of Z or GZ.

Gzexe: compressing executable files

Unarg: Extracting . Arj Files

Zip/unzip: compressing and decompressing . zip Files

User Action Commands

Su: Switch User command

Sudo: A system administrator's identity Execution command

PASSWD: Used to modify the user's password

File connection command

Ln: Creates a connection for the source file and does not copy the source file, that is, it takes up a small amount of space.

Can be divided into software connections and hard links.

Soft Connect: Also known as symbolic Connection, a shortcut is created for a file or directory.

Hard link: Give a file more than one name, put in a different directory, easy for users to use.

The Ln command parameters are as follows:

-F: When creating a connection, delete the file or directory with the same name as the destination object first.

-D: Allows system administrators to hard-link their own directories.

-I: asks the user before deleting the file or directory with the same name as the destination object.

-N: Treats thedestination object as a generic file when creating a soft connection.

-S: Creates a soft connection, which is a symbolic connection.

-V: Displays the file or directory name before connecting.

-B: Files that will be overwritten or deleted at the time of connection are backed up.

Help Command-----Man

otherCommand

who: The display system has those users in use.

-ami Show Current user

-u: Show the user's actions / work

-S: Use a short format to display

-V: Show program version

Free: View memory usage of the current system

Uptime: Shows how long the system has been running

Ps: Show the dynamics of the instantaneous process

Pstree: Displays all the processes in the system in a tree-like manner

Date: Displays or sets the day and time of the system.

Last: Displays the user information of the monthly login system

Kill: kills some specific process

Logout: Exiting the system

Useradd/userdel: Add user / Delete user

Clear: Clear Screen

PASSWD: Set User password

VI Editor

First open a file with the VI command

Last-line mode command:

: N,m w path/filename Save specified range document ( n table Start Row,m table end row)

: q! force quit after making changes to the file

: Q No changes have been made to the file exit

Wq or x Save Exit

DD deletes the cursor in the row

: Set number Displays line numbers

: n jumps to n rows

: S replacement string: s/test/test2/g/g global replacement/can also be substituted with%

/Find String

Common commands for network communication

ARP: Network address display and control

FTP: File transfer

Lftp: File transfer

Mail: Send / receive e-mail

MESG: Allows or denies other users from sending information to the terminal they are using

Mutt e-mail management program

Ncftp : File transfer

Netstat: Displays the network connection . routing table and network interface information

Pine: Send and receive emails, browse newsgroups

Ping: To see if the network is connected smoothly

Ssh: Remote login in Safe mode

Telnet: Telnet

Talk: Talking to another user

Traceroute: Displays the path through which a host was reached and the time it was used.

Wget: Automatically download files from the Internet

Write: Writing information to other user terminals Rlogin: Telnet

Absolute path: such as/etc/init.d
Current directory and upper-level directory:./. /
Home directory: ~/
Switch directory: CD

View Current Process: PS
Execution exit: Exit
View current path: pwd

Clear screen: Clear
To view the current user id:

commands for displaying directories and files

Ls: A command to view all folders.

Dir: command to display the specified folder and directory tree: List directory contents in a tree view

Du: Show directory or file size

What command is used to count the contents of a file? (line number, number of words, number of bytes)
WC command-c counts bytes. -L COUNT the number of rows. -W counts the number of words.

What commands do you use to view a list of used commands?
History
What commands do you use to view IP address and interface information?
Ifconfig

To create an empty file:

Touch

commands for displaying directories and files

Ls: A command to view all folders.

Dir: command to display the specified folder and directory tree: List directory contents in a tree view

Du: Show directory or file size

Linux Common commands