Python Full Stack road Day2 (complement)

First edited September 19, 2017 0:03:16

Summary
I. Operating System Fundamentals
Two. Network Fundamentals
Three. Linux System basics
Homework
Summary of today's summaries

Citation: Mr. Haifeng

1. Review yesterday's basic computer course and memorize it against key knowledge
2. Knowledge of computer operating systems, multi-channel technology and OSI layer five protocols
3. Organize Linux operating system maintenance commands (not finished) &&&&&September 18, 2017 23:57:54

I. Operating System Fundamentals

• Operating system concepts: procedures for coordinating, managing, and controlling computer hardware resources and software resources
  1. The operating system consists of the kernel of the operating system (running in kernel state, managing hardware resources) and system calls (running in the user state, providing the system calling interface for applications written by the application programmer).

1. Features of the operating system:
   1. Provides a better, simpler, clearer model for invoking hardware resources (System call interface)
   2. Order the application's competing requests for hardware resources
2. Multiplexing: Requests for multiple (multiple-way) shared (shared-as-reuse) resources initiated by multiple programs
   • Implementation method:
     1. Multiplexing in space
     2. The reuse of time
        The combination of the above two methods is multi-channel technology
3. processes and Threads : A simple description of the relationship, that is, the thread is part of the process, and all threads share the resources of the process
   (process and thread relationships need to be understood further)

Two. Network Fundamentals

1. OSI Layer Five protocol
   
   

   1. Physical Layer
   2. Data Link Layer
      1. Ethernet Protocol
   3. Network layer
      1. IP protocol
      2. ARP protocol
   4. Transport Layer
      1. TCP protocol:
         • three waves, four handshakes.
           
      2. UDP protocol
   5. Application Layer

2. Realization of network communication

   • To achieve network communication, each host needs to have four elements
     1. The IP address of this machine
     2. Subnet mask
     3. IP address of the gateway
     4. IP address of DNS
   • There are two ways of getting these four elements
     1. Static access
     2. Dynamic acquisition
        
3. Network communication process
   • This paragraph needs to be further deepened and understood and collated

Three. Linux System basics

2. UNIX and Linux operating systems Overview
   1. Unix System features: multiuser and multitasking
   2. Linux
      • shut down Linux system: Init 0
      • Linux Terminal: Virtual Console to operate the system via user input commands
      • virtual Terminal switching method: Ctrl+alt+f[1~6]
      • Normal user and root user login system Tips Characters: $, #
      • Exit command: Exit
4. linux commands and get help
   1. Linux command format: Command parameter Options (Mastering command format commands, options, parameters specific meaning)
      2. Common commands
      • whoami : Get the current user name
      • who : Displays all users who are currently logged on, as well as the current date and time
      • Date : Displays the current date and time of the system; Set the time format Date month day year
      • cal : Displays the calendar for a month in the format Strong>cal month
      • Clear : Clear screen (or ctrl+l)
      • su : switch from the current user to another specified Other users, such as the cut to root user command: Su–root (where-display last logon time)
      • passwd : Modify user passwords, such as Pass WD User name
      • man : Get instructions for using a Linux command, such as view the instructions for using the SU command: Man su
      • --help : The same man command, such as the View LS command help command is: (Do not use the man method) Ls–-help
6. Browse, manage, and maintain directory files (i)
   1. File system directory
      1. Top-level root directory: Use "/" to represent
      2. Two special directories in the file system
         • . Represents the current directory, which is the working directory where the user resides
         • .. Represents the parent directory, which is the previous level of the current directory
   2. Some important directories in the Linux system
      • bin: Used to store common executable files
      • sbin: The executable file used to store the system
      • home directory : Used to store the user's own files or directories, superuser root home directory is/root, and the normal user's home directory is stored in the/s directory, and use the user name as the last level directory (home directory) name, such as the cat user's home directory is/ Home/cat
      • dev: Device files directory
      • etc: Configuration file directory
      • mount point (directory): Typically removable hardware is mounted under the/media or/mnt directory
   3. Absolute directories and relative paths
      1. Definition of Absolute path: You must start with a forward slash (/) and, in any case, you can find the desired file using an absolute path
      2. Definition of relative path: Do not start with a forward slash (/)
7. Browse, manage, and maintain directory files (ii)
   2. PWD and CD identify and switch directories
      • pwd: Displays the user's current working directory as an absolute path
      • CD: Toggle the current directory
      • CD.. : Go to the top level directory
      • CD ~: Switch to the user's home directory
      • CD: with CD ~, can also switch to the user's home directory
      • cd–: working directory before switching to user
      • CD directory name : switch to the specified directory
   4. LS lists the contents of the directory
      • Lists the current directory (the default is the current directory) or the contents of the specified directory
      • ls-a: lists all files under the directory, including "." The implied file at the beginning
      • ls–all: With Ls–a
      • ls–l: lists details of each file in a directory, long list mode, and does not show hidden files
      • ls–d: displays only the directory name itself and does not display a list of contents under the directory
   6. CP Copy files and directories
      • Copies a file (which can be multiple) into a file of a specified path or into a directory of a specified path.
      • CP Source File Destination file
      • –r (Recursive, recursive): replicates the directory recursively. When copying a directory, copy all of the contents of that directory, including the entire contents of the subdirectory
      • - F (Force, mandatory): Do not ask for direct force replication when the destination file already exists
   8. MV Move and modify file and directory names
      • ****:
      • ****:
   10. mkdir Creating a Directory
   12. Touch Create File
   14. RM Delete File
   16. RmDir or rm–r Delete a directory
   18. Cat browses the contents of the body file
   20. Head Browse the contents of the file
   22. Tail Browsing the contents of a file
   24. More Browse files
       • ****:

Homework

2. Linux system basics. Jobs
   1) required to log on to the system as the root user, right-click on the desktop to open the terminal to view the current login Linux system used by the user name
   2) See which users are working on the system
   3) The current time of modification is August 26, 2018 11:28
   4) View October 2015 calendar
   5) Use two methods to view the instructions for using the LS command
   6) Clear the screen
   7) Create a new Tom user with the "Useradd Tom" command and set the password "123" for the Tom User
   8) Switch the current user to Tom
   9) View the user name used by the current login Linux system
   Homework Delivered: Linux system basics. Jobs
4. Browse, manage, and maintain directory files (i). Job
   1) Open Linux operating system and require root user login to Gnome GUI
   2) Right-click on the desktop to open the terminal and use "Useradd Lucy" command to create Lucy user
   3) Use the mouse to click on the method to enter the root directory
   4. Tap into the root user's home directory
   5. Tap into the home directory of the Lucy user
   6. Tap into the directory used to store the frequently used executable files.
   7. Tap into the directory where the executable file for the system is stored
   8) Click to enter the device file directory
   9) Click to enter the profile directory
   submitted assignments: Browse, manage, and maintain catalog files (i). Job
6. Browse, manage, and maintain directory files (ii). Job
   1) turn on the Linux operating system and require the root user to log in to the Gnome GUI, right click on the desktop to open the terminal
   2) Use the command to switch to the root user's home directory
   3) Determine the working directory where the current user is located
   4) Create a directory WG
   5) Create a new file in the WG directory using the absolute path method a.txt
   6) Enter the WG directory
   7) Create a new WG01 directory and B.txt file in the current directory using a relative path method
   8) List The contents of the current directory in long list format
   9) Delete Empty directory wg01
   10) go to the top level working directory
   11) Force Delete non-empty directory WG
   12) Copy/etc/passwd to current directory, named File1
   13) Read-only view of the contents of the File1 file in a non-stop manner
   14) View the first 3 lines of the File1 file
   15) View the following 2 lines of the File1 file
   16) View the contents of the File1 file as a percentage of the page
   17) The method of turning pages above page view the contents of the File1 file

Summary today

1. Multi-channel technology, OSI Five layer protocol, TCP three wave, four handshake need to deepen the impression
2. The realization and process of network communication need to be further collated and understood
3. Linux operating system maintenance common commands need to deepen impressions &&&&&September 19, 2017 0:01:40

Python Full Stack road Day2 (complement)