How to handle when the receiving theme/window already has the files?

[lordspace]

When the files are copied from one place to another there is no warning that some files will be overridden.
How can we handle this?

Ask the user to pick one of the options?

• override all
• skip existing files
• rename old (and copy new)
• something else?

[chozze]

Suggested options sounds good, should cover all requirements.
I'll make that happen.
rename old (and copy new) => how do you want to handle renaming? file.php => file_old.php?