What is cp command with tilde in final part of destination?

Question

For example:

sudo cp /etc/apt/sources.list /etc/apt/sources.list~

With this command I not see any changes.
What does the final tilde do?

Answer 1

The final tilde is just a part of the filename. This command should copy the file /etc/apt/sources.list to a new file with the name /etc/apt/sources.list~. However, if the second file existed before, it is possible that you don't see any changes.