The first part of Big Data Linux learning Note1

1. The operating system consists of the following:

Principle of 2.Linux:

(1) Everything is file, the operation in Linux is for the file.

(2) The configuration file is in plain text format (ASCII format or string format)

3.Linux user Interface

(1) GUI (Graphic User Interface)

(2) CLT interface (Command line Interface)

(3) The nature of the user interface: software for operating system and user interaction

4. Format of the command

5. Path

(1) Absolute path: The essence is the root directory as the starting point with the goal as the end of a path, its disadvantage is: so the programmer must be completely familiar with the overall directory structure of the entire file

(2) Relative path: A pathway that starts with the current working directory and ends with a goal

6. Commands to view Help files

Any command needs to be screened for its type before it can be viewed.

(1) Type command: Gets the type of command

If the description for the BUILTIN type is a command built into the system, viewing the unseen help document can be accomplished by using the Assist command

If not found is the external command, refer to the file's help document needs to use the man command to implement

7. Description of some of the commands

(1) Catalogue:

Working directory (working directory),

Present directory (current directory)

Pwd:printing working Directory

LS (list, listing)
-L: Display file-specific information in long form
(2) file type:
-: Normal file (f)
D: Catalog file (direction)
B: Block device files (blocks): input and output devices without any order, such as optical drives
C: Character device files (character): input and output sequential devices such as keyboards, monitors
L: Symbolic Link files (symbolic link file): That is, the hyperlink file type
P: Command pipe file (pipe)
S: Socket file (socket)
(3) file permissions:

9-bit, each 3-bit group, 3 groups of Permissions User,group,other User (U,g,o) is set for users themselves, user group members, and other users ' permissions

Each group: rwx (Read, write, execute), r--, first group: The owner-user right of the file. Group Two: Group user rights for files, Group Three: other user rights
Number of hard links to files
Owner of the file
Genus Group of files
File size (size), in bytes (bite)
Timestamp (timestamp): Last Modified Time
Access: Access
Modified: Modify, the file content has changed
Change: change,metadata, meta data
-H: Do unit conversions
-A: Show hidden files starting with.
. Represents the current directory
.. Represents the parent directory
-A
-D: Display the directory's own properties
-i:index node, inode
-R: Reverse Display
-R: Recursive (Recursive) display

Cd:change Directory
Home directories, home directories, home directory
CD ~username: Enter the home directory of the specified user
CD-: Switch back and forth between the current directory and the previous directory

Command type:
Built-in command (shell built-in), internal, built-in
External command: There is an executable file corresponding to the command name in a path on the file system

Type: display specifies which type to belong to
Date: Time Management
Linux:rtc

Hardware clock
System clock

Command manual: Manual
Mans COMMAND

Whatis COMMAND

Mans:
Name: command names and features brief description
Synopsis: Usage notes, including available options
DESCRIPTION: A detailed description of the command function, which may include the meaning of each option
Options: Explaining the meaning of each option
Files: The configuration file associated with this command
BUGS:
EXAMPLES: Using the example
See ALSO: Another reference

Flip Screen:
Turn back one screen: SPACE
Turn One screen forward: b
Turn back one line: ENTER
Turn One line forward: K

Find:
/keyword: Backwards
N: Next
N: Previous

Q: Exit

The first part of Big Data Linux learning Note1