linux 个人笔记导出之网络，防火墙，定时，权限，后台

文章目录

- contab定时
- [permission 权限](#permission 权限)
- [backstage 后台任务](#backstage 后台任务)
- 防火墙
- [net 网络](#net 网络)
- - - lsof检查端口进程
    - [telnet 测试远程服务器端口](#telnet 测试远程服务器端口)
    - [ss netstat](#ss netstat)
    - nmap
    - curl
    - - [nslookup 查看域名解析](#nslookup 查看域名解析)
        
        [获取网卡 en0 ipconfig](#获取网卡 en0 ipconfig)

后面才意识到，很多看看，了解知道有这么回事就行

contab定时

explanation

text 复制代码

* * * * *
│ │ │ │ │
│ │ │ │ └─ What day of the week (0-7) (0 or 7 is Sunday)
│ │ │ └─── Month (1-12)
│ │ └───── Date (1-31)
│ └─────── Hour (0-23)
└───────── Minute (0-59)

example

bash 复制代码

# Executed at midnight every day
0 0 * * * /root/xxxx/cleanshell/clean-es-posts.sh

# every Monday morning
0 3 * * 1 /root/xxxxx/cleanshell/clean-es-posts.sh

# first day of each month.
0 3 1 * * /root/xxxxx/cleanshell/clean-es-posts.sh

# three o 'clock every afternoo
0 15 * * * /root/xxxxx/cleanshell/clean-es-posts.sh

# every hour
0 * * * * /root/ xxxxx/cleanshell/clean-es-posts.sh

permission 权限

755 ： read write ex

bash 复制代码

chmod 750 file1.txt # set the permission as rwxr-x---（750）
umask -> set to count the permission

use chown / chrgp to change the owner / group of a file

/root 中的再怎么加权限都不行的

backstage 后台任务

bash 复制代码

sleep 1000 & 
# set a Background process, sleep 1000s, &: put to the background ,Prevent blocking of the current shell
jobs 
jobs -l  # check the background process in the current terminal
killall sleep # stop all the sleep progress 

# Front-end and back-end switching
sleep 1000 #fg frontgroud 
Crtl+Z -> put to the background 
jobs 
fg %1 # put to fg, mission %1
Crtl+C to stop

ps aux：All running processes (including other users, endpoints, daemons)

jobs： Only the background/pause tasks started by the current terminal

nohup : taks may be terminated when the terminal is closed, use nohup to solve

bash 复制代码

nohup sleep 1000 &
ps aux | grep sleep 
cat nohup.out # nohup will generate the nohup.out file, sleep has no output, so it is empty

防火墙

bash 复制代码

sudo ufw status
sudo ufw allow 80 
sudo ufw allow 443 
sudo ufw reload

net 网络

lsof检查端口进程

bash 复制代码

lsof -i :7000

telnet 测试远程服务器端口

bash 复制代码

telnet 142.171.225.226 7000

ss netstat

bash 复制代码

ip addr #Check the ip address, have different net card 
ss -tuln  # check the listening ports
ss -tuln | grep 80 # 这时候nginx就在监听了
netstat -tulnp # like ss


netstat -tuln | grep 7000 # 检查端口
netstat -tuln  容器内部也可以看监听的

bash 复制代码

sudo netstat/ss -tuln | grep -E ':80|:443'

nmap

bash 复制代码

nmap -p 80,443 142.171.225.226

curl

Check the response header and status code

bfe: baidu's load balancing server -> 302 means redirection

-L：Auto-follow redirection- > will show the true result

-v: Displays detailed request and response procedures

-s : no output

-o : output file like : curl -o baidu.html https://baidu.com

check mywebsite:

bash 复制代码

curl -I http://231114.top

nslookup 查看域名解析

bash 复制代码

nslookup b1a6ae8ec37d.ngrok-free.app
dig 231114.top

获取网卡 en0 ipconfig

复制代码

ipconfig getifaddr en0