The information used by cron is stored in crontabs. There are two different places where one usually finds them. The crontab valid system-wide is normaly stored in /etc/crontab.
Note: /etc/crontab can only be edited by root! kcrontab will not let your read it if you are not root.
User crontabs are usually stored in /var/cron/tables/ and carry the name of your user-account. Example: If you log in as donald your user crontab will possibly be /var/cron/tables/donald.
When you start kcrontab the program automatically tries to read the
user crontab. The contents of this table will be displayed in the main
window. (See picture further down) The name of the currently read crontab is allways shown in the
window title.
Note: If you have logged in as root you can read the system crontab by
using the option Read system crontab in the File menu.
kcrontab main window
As you can see the contents of the loaded crontab is displayed in the form of a list. There are 7 columns which have the following meanings: