Checking ISO and/or File Images via CLI

If you have downloaded an iso or image and you want to check that image/iso hasn’t been tampered or corrupted. Ubuntu has a md5 and sha hash checker pre-installed within the OS.

For MD5 checking you will use md5sum

md5sum path/to/image

kmarquis@marquis:/tmp$ md5sum ubuntu-14.04.2-server-amd64.iso 
83aabd8dcf1e8f469f3c72fff2375195  ubuntu-14.04.2-server-amd64.iso

For Sha checking, you will use one of the below (depending on the hashing value)

kmarquis@marquis:~$ sha
sha1sum       sha256sum     sha512sum     shasum        
sha224sum     sha384sum     shadowconfig

sha1 path/to/image

kmarquis@marquis:/tmp$ sha1sum ubuntu-14.04.2-server-amd64.iso 
3bfa6eac84d527380d0cc52db9092cde127f161e  ubuntu-14.04.2-server-amd64.iso

You then can check the md5/sha hashes against the known correct has values. If they match (which these do):

You are good to go, knowing you have a legit version! :D