While I agree that find has weird quirks to my liking, your example is not a great one. I would write the find as follows:

`find /prog -type f -size +500k -name core -delete`

Alternative:

`find /prog -type f -size +500k -name core -exec rm -v {} +`

For extra context:

`-print` will just show you the results before `rm`'ing.

When the command ends with `\;`, the command will be repeated for every match. If the command ends with `+`, the results are appended until max args is reached (and then repeated). This is not always possible, but when it is, it's way easier to use. Less calls to the command, but certainly useful when appending the command after an ssh command, which would mean any number of extra `\` to escape the original `\`...