软件包：cowdancer（0.90） [debports]
Copy-on-write directory tree utility
Tries to make copy-on-write semantics upon hard-link copied directory trees generated with 'cp -la'
'cow-shell' command invokes a shell session. Within that session, under the directory cow-shell was invoked, cowdancer will create a new file when existing i-nodes are opened for write. Useful for quick scratch workspace and experimentation.
For a useful Debian tool, try cowbuilder.