How to check an Ubuntu .iso file

After downloading an .iso file from ubuntu.com (please tick the box under the “Start Download” green button if you want the alternate version and choose a mirror close to your location), you need to verify that the .iso file is not corrupted before you can use it to install Ubuntu.

Ubuntu provides the md5 hashes of all the released .iso files. Please read here for more information about md5 (Message-Digest algorithm 5). To check the file, we’ll use md5sum: