Rhcsa first day

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This article is my study notes , For reference only , If offended , Please contact the author for deletion ！！！

One 、liunx Installation of operating system  

With kali For example ：

1. Download the system image file

    First download the system image , Get into kali Official website , choice 64 Bit system . stay Downloads Choose from Download Kali Linux, As shown in the figure below .

2. Create a new virtual machine

    stay vm It's a new virtual machine , Choose the typical directly , And then the next step .

3. Select the middle Setup CD image file , Go to the file to find the image you downloaded .

4. Name the virtual machine and choose the installation location

5. Select the disk size for the virtual machine ..

6. Move on to the next step , As shown in the figure, we can change the virtual machine hardware . Click Custom hardware .

7. Just change the memory and processor . It can be adjusted according to the configuration of your computer . As shown in the figure .

8. Click Close , Then turn on the virtual machine .

9 choice Graphical install 

10 Choose simplified Chinese , Choose your region China , Select keyboard mapping , chinese

11 At this step, select the host name , Just customize

12. Set the power on password .

13. Automatic installation system .

14. Wait for the system to restart after installation .

15. installation is complete kali The interface is as follows

Two 、 Change the hostname to server.local

[[email protected] ~]# hostname server.local
[[email protected] ~]# hostname
server.local

3、 ... and 、 Crack the code

1. Press... On the startup interface e key , Enter system rescue mode

2. stay quiet Add instructions after rd.break

 3. Press down CTRL+x start-up , Enter command line mode .

4. Reset password .

switch_root:/# mount -o remount,rw /sysroot
switch_root:/# chroot /sysroot

#  Reset password 
sh-4.4# echo “ New password ”|passwd --stdin root

#  Forget SELinux Record ( Must operate , Otherwise, the new password will not take effect )
sh-4.4# touch /.autorelabel

5. Exit twice , Forcibly restart the system .

6. Log in to your account with your new password , If login is successful , It proves that the cracking is successful .

Four 、 Course summary  

1. Composition of computer ：

    1、 controller , It's the central nervous system of the whole computer , Control according to the procedure requirements , Coordinate the work of each part of the computer and the memory and peripherals

Visit, etc .

    2、 Arithmetic unit , The function is to perform various Arithmetic operations and Logical operations .

    3、 Memory , The function is to store programs 、 Data and various signals 、 Information such as orders .

    4、 input device , The function of the input device is to program 、 Raw data 、 written words 、 character 、 Control command or data collected on site and other information input

Enter the computer . Common input devices are keyboards 、 Mouse, etc. .

    5、 Output devices , It outputs the information calculated by the computer . Common output devices include display terminals 、 The printer 、 Plotters, etc .  

2. The function of a computer ： Receive instructions and data from input devices , after cpu The data and logical operation processing of generate useful information to store or output to the screen .

3. What is the operating system ？ operating system （Operating System, abbreviation OS） It is a plan to manage and control computer hardware and software resources Computer program , It is the first layer of software configured on computer hardware , Any other software must be supported by the operating system .

     The main work of the operating system is realized by the operating system kernel , The operating system kernel provides a series of multi kernel functions with predetermined functions , Through a set of interfaces called system calls （ Application programming interface API, A collection of all system calls provided by the operating system implementation , Is the interface between the application and the system ） Present to the user .

Common operating systems ：UNIX、Linux class 、MacOS、Windows class 、iOS、Android、ChromeOS wait

4. Functions of the operating system kernel ：

    （1） System call interface ： The programmer communicates with the kernel through this interface

    （2） Procedure management ： A computer may have a lot of work waiting at the same time CPU Operation processing , The kernel must be able to control these jobs at this time , Give Way CPU Only by allocating resources effectively .

    （3） memory management ： Control the memory management of the whole system , All program code and data of the system must be stored in the kernel first , Usually, the kernel will provide the function of virtual memory , When the memory is insufficient, it can provide the function of memory exchange .

    （4） File system management ： Such as data input and output , There is also support for different file formats .

    （5） Device drivers ： Hardware management is one of the main tasks of the kernel , The device driver is the code that the kernel manages the hardware , equipment The driver of can make the hardware ready to work , Always waiting for the call of the program . Fortunately, there are so-called “ Loadable modules ” work can , You can edit the driver as a module , There is no need to recompile the kernel .

5.liunx Introduction to operating system

6.Linux Characteristics

    Open source

    True multi-user multitasking

    Fully compatible with POSIX standard

    Powerful portability

    Rich network functions

    Good user interface

    Reliable system security

    High stability

7. build liunx learning environment

    Install virtual machine

    install linux operating system

    install xshell

8. Get ready root Sign in , obtain ip Address remote login

9. Zoom in / Reduce the font size

10. Basic knowledge of

     

terminal （shell command interpreter bash sh）

View the current linux Release information for

[[email protected] ~]# cat /etc/redhat-release
CentOS Linux release 8.3.2011

Shell Prompt ：# and $

     For ordinary users ,Base shell The default prompt is the dollar sign $ ;

     For super users （root user ）,Bash Shell The default prompt is pound sign # .

        Normal user login ： [ Currently logged in user @ Host name Current working directory ] $

       root The user login ： [[email protected] Host name Current working directory ] #

see IP Address

   

   ifconfig    ip-a

Modify hostname

[[email protected] ~]# hostname server # Temporary modification , restart linux System later fails 
[[email protected] ~]# hostnamectl set-hostname server # permanent , What is modified is the file content . restart linux The system still takes effect after 
# View the hostname profile 
[[email protected] ~]# cat /etc/hostname
server

View the current working directory ： pwd

[[email protected] ~]# pwd
/root
[[email protected] ~]# su - centos
Last login: Mon Jun 6 15:16:56 CST 2022 on pts/0
[[email protected] ~]$ pwd
/home/centos

Change the current working directory , That is, switch directories

 Absolute path （ With / The way to start ）
 Relative paths （ Not in / The way to start ）
[[email protected] ~]# cd /
[[email protected] /]# cd -  notes ： This operation will return you to the directory you last switched 
/root
[[email protected] ~]#
[[email protected] /]# cd /home
[[email protected] home]# cd /home/centos
[[email protected] centos]# cd ~  notes ：~ Represents the home directory of the current user , The current user is root, It means 
root User's home directory 
[[email protected] ~]# cd ..  notes ：.. Represents the upper level directory of the current working directory 
[[email protected] /]# cd .  notes ：. Represents current work 

Reset root password （ See the above for the specific process ）