копировать файлы (copy files)
Использование в приложениях (Application usage)
The set-user-ID and set-group-ID bits are explicitly cleared when
files are created. This is to prevent users from creating
programs that are set-user-ID or set-group-ID to them when
copying files or to make set-user-ID or set-group-ID files
accessible to new groups of users. For example, if a file is
set-user-ID and the copy has a different group ID than the
source, a new group of users has execute permission to a set-
user-ID program than did previously. In particular, this is a
problem for superusers copying users' trees.
