Linux Advanced Applications

Linux

• More stable and reliable than windows
• Unix is ​​also better, but it is commercial and generally tied to the hardware

Nginx

• HTTP server handles http requests from browsers
• wsgi gateway

MySQL

• PDB relational database
• Persistence data persistence
• SQL

Redis

• NoSQL(Not only SQL)
• High Speed ​​Cache
• Commonly used, more visited here

Cluster-cluster

• • Load Balance
• • Keepalived Hot Standby Active-Active
• • Nginx/LVS + Keepalived Ali does better

awk

• ps -aux | grep mysql | awk ‘{print $2}’| xargs kill -9 2> error.log
• code inside single quotes
• Ability to delete found processes

xargs

• You can pass the obtained value as a parameter to other functions

Tips Install Python3 under Linux

Unzip + configure environment variables

• In the home directory vim .bash_profile
• find PATH=$PATH:$HOME/bin
• Add :root PATH= after$PATH:$HOME/bin:/root
• Pay attention to modify this point and do not modify it wrong, otherwise you will not be able to execute any command
• source .bash_profile re-execute this file

Login to execute

• Can modify .bash_profile or .bashrc
• After logging in again, the content you added will be automatically executed

Boot execution

• Can modify /etc/rc.local

Scheduled execution -crond

• crontab -e Edit scheduled tasks
• crontab -l lists running scheduled tasks

"""
之后会自动进入vim中
在第一行
五个星号分别表示分钟 小时 天 月份 星期
* * * * * 后面加入要执行的命令

* 7,18 3 * * 这样表示每个月的3号的7点到18点的每分钟都执行
如果不是很熟悉怎么写，可以用网上的cton表达式生成器

"""

advanced vim usage

• :addr/addrev main if name == ' main ': You can abbreviate the definition of the following statement in edit mode, press main and press space or press Enter to call directly
• The :map shortcut key command can define a shortcut key to execute the command

Shell

• Can execute system commands

sum=0
int=1
while(($int<=100))
do
sum=`expr $sum + $int`
let "int++"
done
echo $sum

type of language

• interpreted language
  
  • Python Shell/Scripting Language PHP JavaScript
• compiled language
  
  • c language c++
• Assembly language
  
  • Compile machine language 0s and 1s into mnemonics
• machine language
  
  • 0，1
• The higher the execution efficiency, the lower the development efficiency.