GSummer is a simple graphical application used to validate file checksums.
Just run GSummer, choose file to validate, select hash algorithm, paste checksum provided by the file creator and hit "Validate".
Once the validation is finished, you will know whether file is ok or damaged.
Basically there's no need to install GSummer (although lack of installation script makes its version 0.9.4 rather than 1.0) and thus the installation procedure is as follows:
distdirectory to your liking and copy it wherever you like.
You can start the application by issuing the command
application_directory/gsummer on the command
To preload GSummer with file to check, you have to pass it the file name parameter on the command
gsummer -f file_to_check.
You can also create
.desktop file to run the application with your desktop environment.