Reference to a hash, in which each key is a directory to copy from and the value is the directory to copy into. The whole tree below the “from” directory is copied, with timestamps and permissions preserved.

The hash has two additional keys: read and write. After copying everything, install writes the list of target files to the file named by $hashref->{write}. If there is another file named by $hashref->{read}, its contents are merged into the written file.

Verbose switch.

Don’t-really-do-it switch.