The files that specify the different folders and buttons of the Gnome user interface are somehow really badly distributed all over the place. Here are just a few of the more common locations:
Icons in the panel: ~/.gnome2/panel2.d/default/launchers/
Contents of Start Here: ~/.gnome2/vfolders/start-here/
user's Home, Trash and Start Here: ~/.gnome-desktop/
BackupPC seems to be a cool application. Except for the fact that it is not easy to start working with in the first place. I downloaded BackupPC-2.0.0.tar.gz and installed it into the directory /usr/local/backuppc. Then I executed the config.pl and answered all I could. The place where I want to backup my stuff is my second hard drive /dev/hdb5 which is formatted as reiserfs and mounted at /mnt/hdb. After the config script there was a new directory in /mnt/hdb: backuppc, which contained 6 other directories: conf, cpool, log, pc, pool and trash.
If you want to execute a command with root privileges, you normally use the command "sudo". But of course you can execute a command also as any other user. E.g. I need to execute some script for my backup as user "backuppc". then I just type:
sudo -u backuppc /usr/local/backuppc/bin/BackupPC_serverMesg status info
Instead of the username (backuppc) one can also use the user id (uid).