current position:Home>[Linux 4] timed task scheduling and process service management, Java Architect with ten years of development experience

[Linux 4] timed task scheduling and process service management, Java Architect with ten years of development experience

2022-01-26 21:35:08 m0_ fifty-four million eight hundred and sixty-one thousand fou

(1) Every other minute , Append the current date information to /tmp/mydate In file

*/1 * * * * date >> /tmp/mydate.txt

(2) Every other minute , Append the current date and calendar to /tmp/mydate In file

step :

  1. vim /home/my.sh Write content date >> /home/mydate and cal >> /home/mydate

  2. to my.sh Add execution permission ,chmod u+x /home/my.sh

  3. crontab -e increase  */1 * * * *  /home/my.sh

(3) Every morning 2:00 take mysql database testdb, Backup to file .

Instructions :mysqldump -u root -p password database > /home/db.bak

  1. crontab -e

  2. 0 2 * * *  mysqldump -u root -proot testdb > /home/db.bak

4、at Timing task

(1)at: One time scheduled tasks

(2)at Command format

at [ Options ][ Time ]

Ctrl + D end at Command input

Two 、Linux Partition and mount


1、 Partition command :fdisk /dev/sdb

2、 Disk status query

Basic grammar :df -h

3、 Disk condition utility instruction

![](https://img-blog.csdnimg.cn/20210415211144484.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2d1b3J1aV9qYXZh,size_16,color_FFFFFF,

《 A big factory Java Analysis of interview questions + Back end development learning notes + The latest architecture explanation video + Practical project source code handout 》

【docs.qq.com/doc/DSmxTbFJ1cmN1R2dB】 Full content open source sharing

t_70)

3、 ... and 、 The network configuration


1、NAT The network configuration

2、 configure gateway 192.168.2

3、 Design host names and hosts mapping

Modify the file in /etc/hostname Appoint

Four 、 Process management


1、 Process number

stay Linux in , Each executed program is called a process , Each process is assigned a ID Number (pid, Process number ).

2、ps Instructions

Display the process executed by the system

attribute :

-a: Display all process information of the current terminal

-u: Display process information in user's format

-x: Display the parameters of the background process

Pagination display :ps -aux | more

Filter display :ps -aux | grep sshd

3、ps Show detailed information

  1. USER: User name

  2. PID: Process number

  3. %CPU: Process occupation CPU Percent of

  4. VSZ: Virtual memory size occupied by the process ( Company :KB)

  5. RSS: The physical memory size occupied by the process ( Company :KB)

  6. TT: Terminal name , abbreviation

  7. STAT: Process status (S- sleep ,s- Indicates that the process is the forerunner of the session ,N- Indicates that the process has a lower priority than normal ,R- Running ,D- Wait for a short time ,Z- The dead process ,T- Being tracked or stopped, etc )

  8. STARTED: Start time of the process

  9. TIME:CPU Time , That is, process use CPU The total time of

  10. COMMAND: Commands and parameters used to start the process , If it is too long, the display will be truncated

4、 Terminate the process

kill and killall

Basic grammar :

kill [ Options ] Process number ( Function description : Kill the process by process number )

killall Process name ( Function description : Kill process by process name , Wildcard characters are also supported , This is useful when the system is slow due to excessive load )

Common options :-9 Indicates that the process is forced to stop .

5、 View the process tree

pstree [ Options ], You can more intuitively view the process information

Common options :

-p: Show progress pid

-u: Show users of the process

5、 ... and 、 Service management


1、 brief introduction

The essence of service is process , But it's running in the background , It's usually listening on a certain port , Waiting for requests from other programs , such as mysql、sshd、 Firewall, etc , So we call it a daemon , yes Linux The most important knowledge point in .

2、service Management instructions

  1. service service name [start | stop | restart | reload | status]

  2. stay centos7.0 after , Many services are no longer used service, But use systemctl

  3. service The service of command management is /etc/init.d see

3、chkconfig Instructions

adopt chkconfig You can set self startup for each running level of the service / close .

Basic grammar :

  • chkconfig --list [| grep xxx]

  • chkconfig service name --list

  • chkconfig --level 5 service name on/off

4、systemctl Instructions

Basic grammar :

systemctl [start | stop | restart | reload | status] service name

systemctl The service of command management is /us/lib/systemd/system see

systemctl Set the self starting state of the service

  1. systemctl list-unit-files [|grep service name ]( View service startup status ,grep It can be filtered )

copyright notice
author[m0_ fifty-four million eight hundred and sixty-one thousand fou],Please bring the original link to reprint, thank you.
https://en.cdmana.com/2022/01/202201262135068027.html

Random recommended