md3sum test in Ubuntu

We don't need any GUI application for doing md5sum tests in Ubuntu because it's so easy to just type the following command in a terminal,
md5sum filename Where: filename is replaced with the exact name of the file you want verified
Where: the file to be verified is located in your /home/username folder.

It often takes a short time, depending on the size of the file. A few minutes is not uncommon.

or:

1. Assumed that file.iso and file.iso.md5 are in the same folder

2. type in terminal: md5sum -c file.iso.md5

A tip is to use 'Tab completion' to type the filename, to do that, just type the first two or three letters of the filename to be entered rather than typing it all. Then press your 'Tab' key and the rest of the filename for the file you want verified will be auto-completed. That saves time and typing errors.