Ways to implement task scheduling in Linux

There are two ways to implement a task plan:

1. Perform a task at a future point in time

Two commands can be specified:

At

Batch

(The use of at is only indicated here)

At time

At> COMMAND

At> Ctrl+d

The specified time

Absolute time: hh:mm, DD. Mm. YY, Mm/dd/yy

Relative Time: now+#

Units: minutes, hours, days, weeks

Blur Time: Noon, midnight, teatime

Execution result of the command: send the user as a message to the scheduled task

At-l: Show Job List

at-d at_job_id: Deleting an unfinished job

The following figure:

"Mail 1 view the same content as Ls/var,/cat/etc/issue"

Delete Job 2

2. Perform a task periodically

Command cron to specify

Cron: A service that operates uninterrupted

Anacron:cron, the ability to implement tasks that allow Cron to perform in the past time for a variety of reasons and not perform at once; its configuration file is/etc/anacrontab

Cron:

(1) System cron Task:

Edit/etc/crontab

Format:

Min hours days Week user tasks