Cron and at make it possible to start any command at a given time.
However, many users touch them as little as possible since the configuration is terrifying, even by Linux standards, although the programs are very useful. Two programs may help.
At and Crontab start programs at a given time. At is designed to start something once at the time desired while cron handles calls which you want to be executed on a regular basis. For example if you want to have your artificial web server statistics delivered every 30 minutes, cron is the right program for you. To configure cron, a text file in the directory /var/cron/tabs is used where every user gets his/her own file. In this file the command that you want to execute and the starting time are saved. You should not edit this file on your own but rather use the program crontab. This one is started with the command
>> crontab -eA text editor enables you to edit the file. Especially older distributions use vi as the standard editor and the cryptic commands are often a mystery to many users. Use the variable EDITOR to choose your favorite editor (e.g. export EDITOR="/path/xedit"). However, without your reading the man pages as well, the configuration still should be impossible.
It was obvious that under these circumstances some user would develop a graphical frontend for cron.
Although using TCL/TK8.0, the frontend looks
a little bit old but it is still quite useful. The program offers the configuration
of cron jobs and also the call of at commands.
MAILTO=""into crontab but with Vcron this is not possible.
This program convinces nevertheless especially all those users who do not have KDE running on their computer and therefore cannot use Kcrontab. The few times I normally use crontab in a year I do not want to read the crontab-manpages every time. Furthermore, with a size of only 32kB Vcron is a small program.
The second candidate for the configuration of crontab is Kcrontab. The name already tells us that it is a program for KDE. You can use it with other windowmanagers but the KDE basis packages have to be installed to use e.g. the online help. The frontend looks much better and also the help is bigger than for Vcron. The program does not support the configuration of at jobs, just cron.
To every entry a comment can be added but the command cannot be chosen with a file browser.
Kcrontab does not have a homepage but you can find it at the KDE homepage.