Getting Started with Linux Basics (ii)

the philosophical thinking of Linux :

1. All documents: Abstract almost all resources into the form of documents, including hardware devices, and even communication interfaces;

Open (), read (), write (), close (), delete (), create ()

2. Consists of a number of functions of a single program; A program that only does one thing and does it well; combine small programs to accomplish complex tasks;

3. Try to avoid interacting with users;

Goal: Easy to implement automation tasks in a programmatic way;

4. Use a text file to save configuration information;

One of the philosophical ideas of Linux: All documents

One of the performance: hardware devices are also represented by files

Physical Terminal:/dev/console

Virtual Terminal:/dev/tty# [1,6]

Serial Terminal:/dev/ttys#

Pseudo Terminal:/dev/pts/#

Physical terminal, console: Console

Virtual Terminals: 6, TTY

CTRL+ALT+F[1-6]

Graphics Terminal:

CentOS 6:

Ctrl+alt+f7

CentOS 7:

Which virtual terminal is on, which virtual terminal

Serial Terminal: TTYs

Pseudo Terminal: Pty

View End Devices :

[[email protected] ~]# TTY

/dev/pts/0

To start the GUI:

Run a command on a virtual Terminal interface: StartX &

CLI Interface: command-line interface

[[email protected] ~]# COMMAND

Description

Root: When the logged on user

CENTOS7: Host name of the current host, non-full format, if you want to see the full format: hostname to get

~: The directory in which the user is currently located (current directory), also known as the Working directory (working directory), relative path;

#: Command prompt;

#: Administrator account, for root; Has the highest authority, can perform all operations;

$: Ordinary users, non-root users, do not have administrative rights, can not perform system management class operations;

Note: It is recommended to log in with a non-administrator account, and perform administrative actions to temporarily switch to the administrator and return the operation.

Syntax general format for commands:

# COMMAND [OPTIONS] [ARGUMENTS]

Command: Initiates an order that requests the kernel to run a binary program as a process;

Programs--Process

Static--Dynamic (with life cycle: open to end)

The command itself is an executable program file: A binary-formatted file that may call a shared library file

Most system program files are stored in:

/bin,/sbin,/usr/bin,/usr/sbin,/usr/local/bin,/usr/local/sbin

Normal command:/bin,/usr/bin,/usr/local/bin

Management command:/sbin,/usr/sbin,/usr/local/sbin

Shared libraries:/lib,/lib64,/usr/lib,/usr/lib64,/usr/local/lib,/usr/local/lib64

Library of 32bits:/lib,/usr/lib,/usr/local/lib

Library of 64bits:/lib64,/usr/lib64,/usr/local/lib64

Note: Not all commands have a executable program file that corresponds to a directory

Commands must follow specific format specifications: exe, MSI, ELF (Linux)

The commands are divided into two categories:

Commands that are brought in by the shell program: Built-in commands (BUILTIN)

Standalone executable program file, file name is command name: external command

Shell program is a unique program, responsible for parsing the user-supplied commands;

Environment variables:

Path: The path from which to find the command file for the command string that the user typed; the lookup order: from left to right.

[Email protected] ~]# echo $PATH

/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin

To view the command type:

[[Email protected] ~]# Type CD (command)

CD is a shell builtin

OPTIONS:

There are two forms of the options:

Short options:-C, for example-L,-D

Note: Some of the command options are not-;

If the same command uses multiple short options at the same time, most can be combined:-l-d =-ld

Long options:--word, e.g.--help,--human-readable

Note: The long option cannot be merged ;

Note: Some options can take parameters, which are called option parameters; (command space)

ARGUMENTS:

The action object of the command;

Note: parameters of different commands, some commands can take multiple parameters at the same time, and multiple are separated by whitespace characters;

Example: ls-ld/var/etc

/var and/etc are the objects of action

Get help with using the command:

Internal command:

[[email protected] ~]# help COMMAND

External command:

(1) command to use Help with a brief format

[[email protected] ~]# COMMAND--help

(2) User's Manual: manual

Location:/usr/share/man

[[email protected] ~]# man COMMAND

Section Description:

NAME: Description of functionality

Synopsis: Syntax format

DESCRIPTION: Description

Options: Option

EXAMPLES: Using the example

AUTHOR: Author

BUGS: How to Report program bugs

See ALSO: Reference

Synopsis:

[]: Optional content;

<>: Content that must be provided;

A|b|c: choose one more;

... : Similar content can appear more than one;

User manual: Compressed format of the file, the section of the chapter;/usr/share/man1, Man2, ...

1: User command;

2: System call;

3:C library call;

4: Equipment files and special documents;

5: file format; (configuration file format)

6: Game use help;

7: Miscellaneous;

8: Management tools and guardian;

~]# man CHAPTER (chapter) COMMAND

Example:

[[email protected] ~]# man 1 ls

Note: Not every command has a manual under all chapters

How to view commands in the first few chapters are:

[Email protected] ~]# Whatis ifconfig

Ifconfig (8)-Configure a network interface

Note: Its execution process is the query database;

To manually update the database:

[Email protected] ~]# Makewhatis

The man command to open the manual after the operation method:

Turn screen operation:

SPACEBAR: Turn a screen at the end of the file;

B: Turn the file to the first screen;

Ctrl+d: Half-screen to the tail of the file;

Ctrl+u: Turn half screen to file header;

Enter: Flip a line to the end of the file;

K: Flip a line to the file header;

G: Jump to the last line;

#G: Jumps to the specified line;

1 g: Jump to File header, (G can also jump to the capital)

Text Search:

/keyword: From the file header to the end of the file to find, not distinguish between character case;

Keyword: from the tail of the file to the file header in turn;

N: The same direction as the search command;

N: Opposite to the search command direction;

Exit:

Q:quit

Options:

-m/path/to/somedir: Find the command manual in the specified directory and open it;

(3) Info COMMAND

Get the online documentation for the command;

(4) Many applications will bring their own Help documentation:/usr/share/doc/app-version

README: The relevant information of the program;

Install: Installation help;

Changes: Changes in version iterations;

(5) Official documents for mainstream distribution

Http://www.redhat.com/doc

(6) Official documentation of the program:

"Document" on the official site

(7) Search engine

Google

How to use the Lasso function:

Keyword filetype:pdf (file type search)

Keyword site:domain.tld (domain search)

This article is from the "Disguised Geek" blog, please be sure to keep this source http://waldenkk.blog.51cto.com/2410270/1902370

Getting Started with Linux Basics (ii)