linux[Basic]-19-Scheduled Task service [01]

Scheduled Task Service

One-time Scheduled tasks:

For example: Tonight 11.30 open website service (new website publish)

Long-term planning tasks:

Example: Weekly 1.3.5 pack backup/home/wwwroot to backup.tar.gz

Disposable tasks:

It is implemented by the ATD service/process, and the planned management Operations Command is "at"

Parameters	Role
At < Time >	Schedule a one-time task
ATQ or At-l	View the Task List
at-c Serial Number	previewing tasks and setting up the environment
Atrm	Delete a task

You typically use the AT command to set up scheduled tasks using either interactive or non-interactive methods.

Ctrl+d Save exit after completion

Interactive:

[[email protected] ~]# at 23:30

at> systemctl start httpd

At> <EOT>

Job 2 at Fri Sep 8 23:30:00 2017

[[email protected] ~]# atq # View Task List

2 Fri Sep 8 23:30:00 a root

[[email protected] ~]# at-c 2 # Preview

#!/bin/sh

# Atrun Uid=0 gid=0

# Mail Root 0

Non-interactive: ( transfer directly to the at command using the echo statement )

[Email protected] ~]# echo "systemctl start httpd" | At 23:30

Job 3 at Fri Sep 8 23:30:00

[Email protected] ~]# ATQ

3 Fri Sep 8 23:30:00 a root

[Email protected] ~]# ATRM 3 #删除序号为3的任务

[[email protected] ~]# atq # View Task List

[Email protected] ~]#

Long-term planning tasks:

Cron Service is required to establish long-term planning tasks

Create and edit a scheduled task:crontab-e [-u user Name]

View Scheduled tasks:crontab-l [-u user Name]

Delete Scheduled task:Crontab-r [-u user Name]

Edit a fixed format:

* * * * * (full path command)

Available cron Service Settings 1.3.5 of the morning 3.25 backup/home/wwwroot directory for backup.tar.gz

But the command in the inside must take the full path (because of the problem of environment variables)

The method for querying the full path of a command is:

[email protected] ~]# which tar

/usr/bin/tar

To start editing a scheduled task:

[Email protected] ~]# CRONTAB-E

no crontab for root-using an empty one

Crontab:installing New Crontab

[Email protected] ~]# crontab-l

* * 1,3,5/USR/BIN/TAR-ZVCF backup.tar.gz/home/wwwroot

[Email protected] ~]#

The cache file in the TMP directory is emptied by setting the 1 o'clock in the morning of the week 1-5:

[Email protected] ~]# CRONTAB-E

crontab:installing New Crontab

[Email protected] ~]# crontab-l

* * 1,3,5/USR/BIN/TAR-ZVCF backup.tar.gz/home/wwwroot

0 * * 1-5/usr/bin/rm-rf/tmp/*

linux[Basic]-19-Scheduled Task service [01]