How to turn off the CentOS-Linux firewall

RedHat yum system

Firewall

• How to close the firewall
  systemctl stop firewalld

• Detect firewall status
  systemctl status firewalld

• Set the firewall to disable startup at boot
  systemctl disable firewalld

SELinux

• Disable SELinux
  setenforce 0

• Get SELinux status
  getenforce

• Permanently disabled
  vi/vim /etc/sysconfig/selinux

Set the partition to be automatically mounted at startup

vi/vim /etc/fstab

This file stores the partition to be automatically mounted at startup

/dev/cdrom /mnt iso9660 defaults 0 0

Mount source Mount point partition type Automatic mount No self-detection at boot

Configure yum source-local yum source

/etc/yum.repos.d/

##yum source configuration file address

Individuals can configure new files in this directory. The files must end with .repo repository warehouse

Example rhel7.repo

[rhel7-source] // Name

name=rhel-sever //Description information

baseurl=file:///mnt //(system disk) file path, note that there are no spaces in file://

enabled=1 //Enable

gpgcheck=0 //Cancel verification

Basic commands

Word sorting

Terminal terminal network-scripts network script passwd password file

nologin prohibit login shutdown shutdown reboot restart
poweroff shutdown Grep filter useradd add user graphical graphics

tty console terminal ()

pts virtual terminal ()

• tty1-tty6

If you enter the graphical interface at the beginning: tty1 is the graphical interface. tty2-6 is a character interface.

Switch the graphical interface to the character interface terminal: Ctrl+Alt+F2-F6

Switch the character interface to another character interface terminal: Alt+F2-F6

Character interface Switch to the graphical interface: Alt+F1

##pts virtual terminal

is the terminal in the graphical interface

Shortcut keys:

Ctrl+Shift+T

Create a new virtual terminal

Ctrl+Shift++

Enlarge the font

Ctrl+-

Reduce font

Alt+numeric keys

Switch terminal

Alt+F4

Close terminal

whoami Function: View the current user
[root@qshu-pc ~]whoami

root

Use who am i Query the pts number corresponding to the current terminal

[root@qshu-pc ~]who am i

root pts/0 2017-7-10 20: 10 (:0)

pts(pseudo-terminal slave) Pseudo terminal: Connect through ssh related terminal. The terminal is: pts

Shell prompt

[root@qshu-pc ~]

[user@host name current directory] prompt root is # and ordinary user is $

Bash Shell basic syntax

Summary of Linux command input rules:

How to enter commands:

Command [Option] ([Parameter]) [Option value] [Parameter Value]

Spaces can be used in combination as splitting parameters

Common options (parameters): -h --help; Features: The options look like: -letters or --plus Word

Basic command operation:

ls command
Function: View what files are in the current directory

Syntax: ls directory, if no directory is added, view the current directory

Parameters:

ls -l

Display in detailed information mode

ls -a

Display all files (including hidden files)

ls -d

Display only directories

ls -h

File size user-friendly DisplayCommon information explanation

. Represents the current directory

.. Represents the parent directory (upper-level directory)

Why do some directory files have What about different colors?

Different colors in the Linux system represent different file types

Blue

Directory/etc

Black

File/etc/passwd

Light Blue

Link/etc/grub2.cfg

Red

Compressed package boot.tar.gz

Green

Executable file/etc/init.d/network

Black background with yellow characters

Device file/dev/sda

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