bug#20094: cp --dry-run

[積丹尼 Dan Jacobson]

Proposal:
add a new "cp --dry-run"
Reason: we want to know what the verbose output of e.g.,
$ cp -i -av /mnt/usb/thumb/ tmp/androidBackup/SDCard
will be without actually running the command first.
We are about to commit to a megabyte copy and we want to be sure where
all those files are exactly going even after understanding all the
documentation, and without needing to do partial "wet" runs etc. etc. etc. etc.

Also add a "mv --dry-run".

Please also document both would normally be used with -v.

In fact cpio (mainly -p) needs a --dry-run too.

Sorry if I have proposed this before, but it's an idea you just can't beat!