What flag does RSYNC use to preserve group ownership of files?

The flag that RSYNC uses to preserve group ownership of files is the -g option. When this flag is included in an RSYNC command, it ensures that the group ownership of the files in the source directory is maintained in the destination directory. This is particularly important in scenarios where files are shared among specific groups, and retaining group ownership is necessary for proper access and permissions management.

By using the -g flag, you can ensure that the files' group attributes are copied over along with the other file attributes, which can include permissions and timestamps, depending on the other flags used in conjunction with -g. This is vital in environments where file accessibility must be controlled and managed based on group memberships, such as in a multi-user server setting.