A Linux-wide command needed

[minthaka]

I'm developing a program, and I would like to add a script, which would download the optional packages for the program. I'm hesitating whether it is worthy to bother myself with this topic, or just to let the end-user take care of the install, but anyway I need an universal command line command which would let the program become super user in order to be able to install few packages. I was thinking about 'su' but first in Ubuntu it does't work very well. The kdesu is hidden somewhere, so the user should create a symlink to it... which is a horror story for an averaged user. Can you suggest me some other command?

[minthaka]

Anyway, life would be easier if the people would be normal,... but somebody have invented 'sudo' instead of a universal 'su' so I have to mess with differences between the distros. This is why it is nearly impossible to write a decent program under Linux!