This paper is participating in the30 years of Linux”Topic essay activity

Liunx has been out for nearly 30 years, how is also the absolute king of IT field, there are a lot of small friends still do not understand Liunx, today I will take you to quickly understand this “big brother”!

Computer Network Notes

Command help:

Command – -help

Manls

Exit man help

The first column:

File properties: file type and file permissions

The D indicates that this is a directory

– The beginning indicates that this is a normal file

L indicates a link file

File permissions:

Read access to Rread

Wwrite write permissions

Rwxrwxrwx

Group 1: represents the owner of the file.

Group 2: indicates the group to which the file belongs

Group 3: indicates the permissions of other users to access files

Column 2: represents the link to the file

Third column: represents the owner of the file

Column 4: The group to which the file belongs

Column 5: Represents the size of the file in bytes

Column 6: indicates the last modification time of the file

Column 7: File name

Linux cp command replication

Directories: copy files and directories

Syntax format:

Cp [parameter] Source file Destination file,

And then the.bak is a copy of the file

Usage:

1. Copy files in the current directory

↓ Copy cp a.cfg a.cfg.bak to the ↓Copy the code

2. Copy the directory under the current directory

Cp -r source directory Destination directory Copy directory must add arguments -r -r, -r, -- recursively copy all contents of the directory and its subdirectories. Example: copy the test directory from the current directory and rename it test_bak cp -r test test_bakCopy the code

3. Copy the contents of the current directory to other directories

Cp [-r] Current directory Contents Other directories

  • Example 1.cp -r test/(test copied to root directory)
  • Example 2.cp -r test /test_bak (test copied to root and renamed test_bak)

4. Copy the contents of other directories to the current directory

Cp [-r] Contents of other directories (including files and directories) Current directory

  • Example: cp /anaconda-ks.cfg.
  • Example: cp /anaconda-ks.cfg./ana.cfg

scp

secure copy(remote file copy program)

Secure replication Remote file replication program

Usage 1. Copy files from the local server to the remote server

Syntax: SCP [-r] local content username @ip:/ directory

Example: SCP -r sofr_frg/ [email protected]:/root/

Copy the soft_frg directory in the current directory on the local server to the /root directory on the remote server

2. Copy the contents of the remote server to the local server

SCP [-r] username@ip :/ local content

Supplement:

/ root directory

/root Home directory of user root

Linux CD command switch

Man can also be viewed

(view) CD –help (view)

cd

Change the shell working directtory

(Switch working directory)

CD usage:

1. Do not add any parameter CD

Action: Back to home directory

In Linux, the root user’s home directory is /root

2. CD catalogue

Function: Switches to the specified directory

Example: CD /

3.cd ..

Function: Returns the upper directory (upper two levels.. /..)

. The superior

4.cd ~

Action: Back to home directory

~ indicates the user’s home directory

5.cd .

Function: CD to current directory

.Current directory

6.cd –

Function: Toggles back and forth between current and previous directories

Supplement:

PWD (Locate the current path)

Prints the current directory/working directory

CTRL + C (force end command) or Enter end line feed

Rm of linu was deleted

Prerequisites for deleting:

Online server, you must make a backup before deleting

rm remove files or directories

Delete a file or directory

Grammar:

[Parameter] File/directory

Common parameters: -r (recursive, recursive delete, first delete inside, then delete outside)

-f (–force forcible deletion, regardless of whether the file exists or not)

Rm -rf File or directory

usage

1. Delete the contents in the current directory

Example: rm -rf test

2. Delete other directories and their contents

Example: rm -rf /test

* Hidden directory cannot be selected

.* You can find hidden directories with dots

This is delete library run necessary skills 😂, careful use!

Linux ls command

ls(list)

Lists the contents of the directory

Grammar:

Ls [Optional] [file]

usage

1: ls

No arguments are added

Function: Lists the names of files and directories in the current directory

2: the ls -l

-l (long, long format)

What it does: Lists the files and files in the current directory in long format. Interest rates

3: LS-AL is the same as ls-a-L

-a Displays all files, including hidden files, all

Function: Lists all articles in the current directory in long format. Files, including hidden files

4: ls [parameter] File name

ls -l abc.txt

Function: View the specified file

5: ls [parameter] directory

ls -l /var/

Function: View the specified directory

Cat, less, more orders

Cat (link files and print their contents to standard output)

(Display file contents on screen (command line))

(View file contents)

Cat [parameter] file

usage

1. View all contents of the file

The cat file

Scenario: Users with low permissions can view file contents

2. View the file content and redirect (input) the file to another file

Cat ifcfg-ens33 > ifc.txt(new file)

3. View the file content and display the line number

Cat-n Specifies the file name

Less (is the opposite of more)

Feel free to view files

More (View file contents in split screen)

(Only press space or Enter to view the new content below)

According to q to exit the

Head (View file header contents)

(View the first ten lines of the file by default)

usage

1. The head file

2. View the specified number of rows

Head -n Number of lines file name

Tail (View file tail contents)

(Default last 10 lines)

Common parameters: -n -f (View file contents in real time)

tail -f -var/log/secure

Linu’s mv command moves

mv move (rename) files

Move or rename files

The mv command has two functions:

1. Move (cut) files or directories

2. Rename a file or directory

grammar

1. Move files in the current directory

Syntax: mv file destination directory

Example: mv anaconda-ks.cfg.bak /

2. Move the directory in the current directory

Syntax: mv Source directory Directory

Example: mv test /

3. Move the contents of other directories to the current directory

Example: MV /test.

4. Rename the file in the current directory

Syntax: mv Old filename New filename

Example: mv anaconda-ks.cfg. Bak ana-ks.cfg

5. Move the files in the current directory to another directory and rename them

Syntax: mv Source file destination directory/new file name

Example: mv Ana-ks. CFG /anac.cfg

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