The first day of Linux system learning

The birth of Unix, 1970-1-1


Kernel function: User input command--------> kernel-------> Hardware


Linux composition = kernel + application


Linux distributions (cont. 1)
The name/version of the release is determined by the issuer
–red Hat Enterprise Linux 5/6/7 RHEL
–suse Linux Enterprise 12
–debian Linux 7.8
–ubuntu Linux 14.10/15.04


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Traditional MBR Partitioning mode
–1~4 a primary partition
–0~3 Primary partition + one extended partition (n logical partitions)


Precautions
–MBR partition table can only record 4 primary partitions, number range 1-4
– When it is necessary to use more than 4 partitions, you need to set up an extended partition (
Primary partition number), the extended partition can have up to 1
– Extended partition as a container of intermediate properties, from which it is again divided
The partition space is a logical partition


File System (Decoration)
Data in space, stored rules, arranged in a way


Typical file system types
–EXT4, fourth generation extended file system, RHEL6 series default
–XFS, advanced log file system, RHEL7 series default
–swap, swap space (virtual memory)

Directory structure

/root directory (computer): Store all data (starting point of Linux system)
/dev: Device files



How disk is represented

HD, indicating IDE device
SD, indicating SCSI device

/dev/sda1/dev/sdb2/dev/sdc3/dev/sdd4
/dev/hda




/DEV/SDA5: First logical partition

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Ctrl+alt: Mouse back to the real machine

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/DEV/VDA1 500M store kernel and boot files
/DEV/VDA2 100G Storage System

/dev/vda3 100G Custom Partition

/DEV/VDA4 Extended Partition

/dev/vda5 8G Swap

Access point: When accessing a device resource, you must pass the access point

Coal mine-----------> openings

The access point for Linux is a directory


/dev/vda1/boot 500M store kernel and boot files
/dev/vda2/100g Storage System
/dev/vda3/data 100G Custom Partition

/DEV/VDA4 Extended Partition
/dev/vda5 8G Swap





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Initialization process
Confirm License Agreement (1---2--and C--c)


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RHEL7 Basic Operation

Virtual Console Toggle (Ctrl + Alt + Fn key combination)
Ctrl + Alt + F1
Ctrl + Alt + F2
Ctrl + Alt + F3
Ctrl + Alt + F4
Ctrl + Alt + F5
Ctrl + Alt + F6

–tty1: Graphical Desktop
–TTY2~TTY6: Character Console

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Pseudo-character terminal

Meaning of the hint identification
–[Current user @ Host name Current Location]

– If the current user is root, the last character is #

– Otherwise, the last character is $


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Use of BASIC commands




View and switch directories
Pwd-print Working Directory
– Purpose: View your current location

Cd-change Directory
– Purpose: Switch working directory
– Format: CD [Destination folder location]

[root@localhost desktop]# pwd #查看当前所在位置
[root@localhost Desktop]# cd/#切换到/directory
[Root@localhost/]# pwd
[Root@localhost/]# ls #查看当前目录下内容

[[email protected]/]# cd/root #切换到/root Directory
[Email protected] ~]# pwd
[[email protected] ~]# ls


Color:
Black: Text File
Blue: Directory



View System-specific versions
[[Email protected] Desktop]# cat/etc/redhat-release

Cat: Dedicated to viewing text file content
-N: Adding line numbers

Full command format:

Command Word option parameter


[Email protected] Desktop]# uname-r #列出内核版本

[Email protected] Desktop]# cat/proc/meminfo #查看内存

[Email protected] Desktop]# lscpu #查看CPU

CTRL + C: End the currently running instruction

[[Email protected] Desktop]# hostname
[Email protected] Desktop]# hostname a.tedu.cn
[[Email protected] Desktop]# hostname

At the opening of a new terminal, the prompt will change

[[Email protected] Desktop]# ifconfig
[[Email protected] Desktop]# ping 127.0.0.1

[Email protected] Desktop]# ifconfig eth0 192.168.1.168
[Email protected] Desktop]# ifconfig eth0
[[Email protected] Desktop]# ping 192.168.1.168


Ls-list
– Format: ls [options] ... [directory or filename] ...

Common Command Options
–-l: Display in long format, displaying detailed properties of directory contents


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Shutdown: Poweroff
[Email protected] ~]# Poweroff

Restart: reboot
[email protected] ~]# reboot


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Common tips:
1. Command not Found!
BASH:CAA: Command not found ...
Bash:caa:command not found ...

Reason:
1. Incorrect command input
2. The command is not installed


[Email protected] Desktop]# lang=en #修改为英文
[[Email protected] Desktop]# LANG=ZH_CN. UTF-8 #修改为中文

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The first day of Linux system learning