Copying of dvd to harddisk, ripping the vobs to harddisk with tools like:
dvdbackup
http://dvd.chevelless230.com/dvdbackup.html
mplayer dvd:// -dumpstream (http://www.mplayerhq.hu)
play_title (from libdvdread guys,
http://linuxvideo.org/cvs/viewcvs.cgi/libdvdread/src/play_title.c)	
tccat from the transcode package
(http://www.theorie.physik.uni-goettingen.de/~ostreich/transcode/)
cpvts
cpdvd
lxdvdrip (all 3 not tested by me)
vobcopy from www.linux-programming-newbie.org 
All of these tools are something similar to vobdec/DVDEcyptor under win
(think so, my vobcopy at least is ;-) 
Robos