at a one-time task settings

at a one-time task settings

• Scheduled Tasks CentOS7 system is provided by at, cronie package, to achieve a one-time, periodic scheduled tasks feature by atd and crond both system services and scheduled tasks were set by at, crontab command

• Atd open system service is a prerequisite for scheduled tasks at a command set

• Program at the command specified set point in time only once, provided that the corresponding system service must have been atd

• Note: Scheduled tasks time, date, time must be scheduled after the current system, otherwise it is impossible to set a scheduled task

• The basic format at the command:

• at [HH: MM] [yyyy-mm-dd] is: at [hh: mm] [Year - Month - Day]

• 　at the command of the order of use:

• View Time -> Set Time -> Enter the command -> ctrl + D to commit the task

• date: confirmation (no longer set the task before the current time) current time

• ctrl + D key combination task can be submitted

• After the time is up you can use: the case of cat View completed tasks

atq command: View preparatory tasks to be performed

• For already set, but the task was not performed, can be viewed by atq command. (Task has been executed does not appear)

• atq view a list of tasks, each task number will not change, even if the numbers 1-5 tasks have been implemented, showing the sixth mission of the serial number is not 6, but will not become 1

  atrm command: delete the specified number of tasks at

• atrm command to remove a number of tasks at, numbers can be viewed atq.

• After deletion at the task does not appear in the results display atq

• at just a one-time task settings are not repeated. If want to repeat the task then use the crontab command set

• crontab periodic task set (task may be repeatedly performed)