AT is a free and open source job scheduler tool for Linux. Using AT command, You can schedule a command to run once at a given time without editing any configuration file.
How to Install AT Command line Tool on Ubuntu
To install AT tool on Ubuntu, run below command in the terminal app (ctrl+alt+t).
sudo apt install at
After that start and enable the at service using below commands.
systemctl start atd
systemctl enable atd
Schedule a Task on Ubuntu Using AT Command
After above steps, you can schedule any command or task.
Example: You can shutdown the system at 11:00 today using below command.
sudo echo "shutdown -h now" | at -m 11:00
To view jobs in at command queue, run below command.
sudo atq
To remove or delete jobs from the above command queue, run atrm command and then identified by their job number like below example.
atrm 1
For the complete usage details run below command.
man at