Allow user to create files but not edit/delete

[Loïc Grenié]

2011/6/7 Colin Law <clanlaw at googlemail.com>:
> Is there a way to setup permissions and ownership such that a user can
> create new files in a particular directory, and can read existing
> ones, but cannot edit or delete existing ones?  By giving ownership of
> the directory and existing files to root,  with permissions 777 on the
> directory and 774 on existing files, then the user has read-only
> access to existing files and can create new files, but unfortunately
> he can delete existing files and re-create them, hence effectively
> editing them.  Is there any way around this?

chmod 1777 dir

     Loïc