KTimer
Countdown timer
KTimer is a little tool to execute programs after some time. It allows you to enter several tasks and to set a timerfor each of them. The timers for each task can be started, stopped, changed, or looped.
KTimer is a countdown timer for running commands after a delay. The countdown can be paused or set to loop continuously. . This package is part of the KDE SC utilities module.
How to install KTimer in Ubuntu
If you are on a supported distro, you can install the application through software center by clicking the below link.
If the above link not working, run the below command in terminal to install ktimer in Ubuntu
sudo apt install ktimer