Crontab-scheduled job

Recently I read some information about crontab and learned about it. It is almost the same as scheduled tasks in windows.

Write your own understanding. If you are wrong, please forgive me ~~~

1. File Location:

Linux:/etc/crontab

AIX:/var/spool/cron/crontabs/

Note: The crontab file in Aix is the same as the user name. If no, no scheduled job for this user is available.

2. crontab Structure

The previous comments are skipped. They mainly talk about how to write and structure scheduled jobs.

AIX: F1 F2 F3 F4 F5 command

F1: The value range of minutes is 0-59.

F2: The Hour value range is 0-23.

F3: Date value range: 1-31

F4: The month value ranges from 1 to 12 or is the first three letters of the month (Case Insensitive)

F5: The value range of the week is 0-7, or the first three letters of the English letter of the day of the week (Case Insensitive). 0, 7 represents Sunday.

Linux: F1 F2 F3 F4 F5 USER command

F1 ~ F5 is the same as that in Aix.

User: the user who runs the command.

3. Parameters

-E: edit the current crontab file or create a new crontab file.

-L list the contents of the crontab file

-R: Delete the crontab file.

The preceding three parameters are common for AIX and Linux. There are many different parameters in Aix and Linux, which can be viewed through man crontab.