If you are working on a project(s) or you are a freelancer, then you need to track your time so as to bill your clients. If you are using Ubuntu, you can install and use Kapow which will help you keep track of time spent working on a project or task.
The user interface of Kapow is very simple and user-friendly. Use the Start/Stop button to clock in and out with the possibility to correct time mistakes by editing saved entries. To install Kapow on Ubuntu (10.04/10.10/11.04/11.10), then follow these instructions:
1. Open the Terminal and run these commands:
sudo apt-add-repository ppa:gottcode/gcppa
sudo apt-get update
sudo apt-get install kapow
2. Use then the dash (Unity) to open Kapow: