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When I burned ubuntu 12.04 LTS CD, I didn't check md5sum of iso file before it. I checked option check for defects and it ran perfectly. I doubt that Iso may be corrupted(Viruses,unofficial moded software etc). How can I check whether Live Ubuntu 12.04 LTS CD is having defects or not ?

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Boot the ubuntu live-disk and click on Try Ubuntu option.Now you can check for errors without installing ubuntu on your hard-disk.

To check the md5sum of the downloaded ubuntu.iso file refer this.

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No k.k. patel is edited my post. How to check if this live cd have viruses ... If a md5sum is answer than how to check md5 without iso and without name of iso file!? – Predrag Dec 10 '13 at 7:19
what's your actual question is? – Avinash Raj Dec 10 '13 at 7:20
If your iso contents viruses , your files in iso would be corrupted and you will get missing files error while checking iso for defects. – K.K Patel Dec 10 '13 at 7:29
Patel thanks, thanks guys, next time edit and tell why you edit it! And do not erase my info... I was write it all again becouse you delete a lot of post... – Predrag Dec 10 '13 at 7:31
@user223942 you can edit your own question. – Avinash Raj Dec 10 '13 at 7:45

This step can be done via a VM or by doing a restart of your PC.

Press ESC or an equivalent to force the PC to boot from the CD/DVD ROM media drive.

A menu will appear with options like "Try Ubuntu without installing". There should be an option for check disc for defects. Select this option to check your media for defects.

If you for some strange reason, do not see the check disc for defects option, the select F6 for other options, and see if you can find it there.

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I was try that but dude edited/deleted my post, part of it... Is option " check disk for defects" check only errors or and viruses etc! – Predrag Dec 10 '13 at 7:26
check disc for defects only verifies the state of the media, whether its corrupted or faulty. A virus is something much more elusive. Though viruses/worms on Linux are less common. You get tools that are specifically build to clean you hard drives while in booting from a media. Hope that helps? – Rosekrans Dec 10 '13 at 7:47
If your iso contents viruses , your files in iso would be corrupted and you will get missing files error while checking iso for defects. – K.K Patel Dec 10 '13 at 7:29 Can anyone else agree with this statement above that K.K Patel posted? – Predrag Jan 25 '14 at 19:46

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