Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I would like to verified if two CD-ROMs (UDF) identical or not.

One cdrom will be read at Windows and the other CD-ROM at Linux, where the CD-ROMs can be with different burning programs. This means that they can be padded with different amount of zeros at the end of the CD-ROMs.

Until know, with ISO files, i used isosize and then with the help of dd and md5sum, a md5sum generated and compared between the two systems. This approach is not possible with UDF CD-ROMs, since isosize is only for ISO CD-ROMs.

dd if=/dev/cdrom bs=2048 count=`isosize -d 2048 /dev/cdrom`| md5sum

Any idea how to compute a md5sum of the CD-ROM without the padded zeros?

share|improve this question
If you have two ISO files, you can use cmp instead of md5sum. Not only will cmp tell you if the files differ, but also at which byte. So you can look at the difference in detail and decide whether it's padding or not. – frostschutz Mar 1 '13 at 1:48
@frostschutz, thank you for your answer. I have two cases, one is the CD-ROM with ISO file system and the other is with UDF file system. – Eagle Mar 1 '13 at 6:09

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.