How to use crontab to add scheduled tasks in Linux

Preface

The Linux system is controlled by the system service crond. There are a lot of planned tasks on the Linux system, so this system service is started by default.

The crontab command is used to set instructions to be executed periodically. This command reads instructions from the standard input device and stores them in the "crontab" file for later reading and execution.

We can look at the status of the crond system service:

From here we can see that the crond service is self-starting (enabled) and running (active)

In addition, since users can set up scheduled tasks themselves, the Linux system also provides users with a command to control scheduled tasks: the crontab command.

crontab

Function: Add, query, and delete system scheduled tasks.

[root@localhost ~]# crontab [options]
Options:
-e: Edit crontab scheduled tasks
-l: Query crontab tasks
-r: Delete all crontab tasks of the current user 12345

[root@localhost ~]# crontab -e
#Enter the crontab editing interface. Will open vim to edit your work#Enter data, the basic format is:
* * * * * command12345

1.Format explanation:

Example:

2. Special Format

Example

3. Import from and export to files

#Import [root@localhost ~]# crontab filename
#Export [root@localhost ~]# crontab -l >filename1234

Example:

Summarize

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