Windows
-------
A SHA-512 hash can be checked on Windows without additional software by using
PowerShell. To get started, open a PowerShell window by launching the "Windows
PowerShell" shortcut in your Start menu.  Run the following command, replacing
"\path\to\file.zip" with the path to any file you want to view the hash of:

    Get-FileHash "\path\to\file.zip" -Algorithm SHA512

A second alternative that does not require additional software is to use the 
following command:

    CertUtil -hashfile "\path\to\file.zip" SHA512

Finally, the third-party program "fsum.exe" can be downloaded from
https://pcwin.com/Utilities/FSUM/index.htm for free and invoked with the
following command:

    fsum -jm -jnc -sha512 "\path\to\file.zip"


macOS
-----
macOS includes commands for viewing different types of hashes. To access them,
launch a Terminal window. You will find it at Finder -> Applications -> Utilities
-> Terminal. To show the SHA-512 hash of a file, run the following command:

    shasum -a 512 "/path/to/file.zip"


Linux
-----
On Linux, access a Terminal and run the following commands to view the hash for 
a file:

    sha512sum "/path/to/file"


Compare the result of the hash function to the result you expected to see.
If it is the same value, the file has not been corrupted, tampered with, or
otherwise altered from the original.