Detailed usage of Task Scheduler (at, crontab) on Linux systems

What we bring to you today is the introduction of the use of at Crontab

• command to run a task at a time

Syntax: at (option) (parameter)

-F: Specifies the task file containing the specific instructions;

-Q: Specifies the queue name for the new task;

-L: Displays a list of tasks to be performed;

-D: Deletes the specified pending task;

-M: Sends an e-mail message to the user after the task executes.

After you finish writing the command, Ctrl+d submit the task.

Example: 1 days after the 4 o'clock in the morning run Echo Taotao

650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M00/72/BA/wKioL1XsOyKTuW2AAACPJuxm7dQ202.jpg "title=" 7.png " alt= "Wkiol1xsoyktuw2aaacpjuxm7dq202.jpg"/>

• Crontab

  Command description: The crontab command is used to submit and manage users ' tasks that need to be performed periodically, similar to the Scheduled tasks under Windows

  Syntax Crontab (option) (parameter)

crontab [-u user] [-l |-r |-e]

-u User: Not to manage your own cron task, but to specify the target user's cron task; Root has the ability to manage other users ' cron tasks; default management of their own;

-l:list, list the tasks;

-r:remove to remove all tasks;

-e:edit, edit, open a default editor for the current shell session to edit the cron task table;

Ctrl+d Submitting a task

Example: I write to/etc/crontab

1, every Monday to Saturday 3:20 A.M., run the CP command to archive the/etc/directory, storage location is/BACKUPS/ETC-YYYY-MM-DD;

3 * * 1-6 root/bin/cp-a/etc//backups/etc-' date +%f ' >/dev/null 2>&1

2, every Sunday 2:30 A.M., run the CP command to backup the/etc/fstab file, the storage location is/BACKUP/FSTAB-YYYY-MM-DD-HH-MM-SS;

3 * * 7 root/bin/cp-a/etc/fstab/backup/fstab-' Date +%y-%m-%d-%h-%m-%s ' >/dev/null 2>&1

3: Every night 12 o'clock, get all the lines in the/proc/meminfo file that begin with S or M, append to the/statistics/meminfo.txt file, and precede the daily message with a similar =============== separator line;

XX * * * root/bin/echo "===============================" >>/statistics/meminfo.txt &&/bin/cat/proc/m Eminfo | Egrep "^s|^m" >>/statistics/meminfo.txt >/dev/null 2>&1

650) this.width=650; "src=" http://s3.51cto.com/wyfs02/M01/72/BA/wKioL1XsQOTiU3PnAAJOLTQpZeE462.jpg "title=" 8.png " alt= "Wkiol1xsqotiu3pnaajoltqpzee462.jpg"/>

Detailed usage of Task Scheduler (at, crontab) on Linux systems