How to convert a DVD to ISO?

On Mac OSX 10.9, how do you convert a DVD into an ISO that I can use with players such as VLC. I wish to achieve this without buying a program.

Steps I have tried:

1) Downloading Mac app Burn. It lets you select a source and save it as a DVD. However, when I do this, the DVD seems to be corrupt: DVDplayer can't load it properly. VLC can load it, but I only if I select the option to bypass the menus (otherwise it can't load it).

2) Using the command line

sudo diskutil unmount /dev/disk1 dd if=/dev/disk1 of=~/myCD.iso bs=2048 conv=sync,notrunc

This makes the ISO, but it's the same problem as (1) above

3) Using the Command Line

hdiutil makehybrid -iso -joliet -o Image.iso /input_path

This gives the error message: makehybrid failed - No such file or directory

4) Using Disk Utility. You can use Disk utility to create an image, but it only seems to be a .dmg file. Ideally, I'd like a solution that does it in one go (i.e. so I don't have to convert the .dmg to .iso) as I have 90+ discs I want to convert.