[1] DUPLICITY(1) manual page ( 版) http://duplicity.nongnu.org/duplicity.1.html#sect7

Copy cloud storage

copy://user[:password]@copy.com/some_dir

[2] sources.list(5) — apt — Debian jessie — Debian Manpages ( ()) https://manpages.debian.org/jessie/apt/sources.list.5.en.html#URI_SPECIFICATION

The copy scheme is identical to the file scheme except that packages are copied into the cache directory instead of used directly at their location. This is useful for people using removable media to copy files around with APT.