Linux Scheduled Tasks

Task scheduling: Refers to a particular command or program that the system executes at a certain time

Task Scheduling classification: 1. System work: Some important work must be performed periodically, such as virus scanning, etc.

2. Individual users work: Individual users may want to execute certain programs.

Use Crontab for task scheduling

1. Set Task Contab–e

2. To perform date>/home/mysate1 at intervals

Want to do date>>/home/mydate2 every 2:00

Can be added in Crontab–e 0 2 * * * DATE>>/HOME/MYDATE2

Time-sharing week (02***date)

3. How to schedule multiple tasks

① write multiple tasks directly in Crontab–e

② can write all tasks to an executable file (Shell programming)

Build the. sh File VI

Writes the command to the. Sh

Modify the executable permissions for the file, and then change the executable

Give the file to Crontab to execute crontab–e (just put the file in)

Stop execution of files Crontab–r

Lists all currently scheduled Tasks Crontab–l

Process: is the program being executed

Thread: ① Lightweight process ② process has separate address space, thread does not have

③ thread cannot exist independently, it is a process created by ④ relatively, the thread consumes less memory and CPU than the process

Foreground process: Can be manipulated on the screen

Background process: The screen can not see the process, the background mode of execution, the general system of services are backstage

Command ps–aux: View process status Kill process number: End Process

Kill–g process Number: Force end process-G table number 9

Killall Process Number: Both the process and its child processes end

Top is similar to the PS command to show the process being executed, while top performs a period of time to refresh the running process

① Monitor specific users top enter and then u go back and enter user name

2 terminating the specified process top enter K Enter to re-lose process number

3 Specify System State Update time TOP–D 10: Update time is 10 seconds

Change the system time

Date Mmddhhmmccyy. Ss

Day of the month, years, seconds.

View Calendar Cal 3 2002

Monitoring network status information

Netstat–an This command to show the current network condition of the entire system

NETSTAT–ANP can know which process number is listening on a port

Use the kill process number to block the port on which the process number is listening

Traceroute: The process of detecting the transmission of packets over a network, from native to remote host full path

Route: View routing in the form of a routing table

command, the file name. MV formerly known as the new name

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Linux Scheduled Tasks