Re: [Duplicity-talk] file selection behavior

[Mathias Rav]

On Sat, 13 Oct 2018 15:44:08 -0400
Jordan Rosenthal via Duplicity-talk <address@hidden> wrote:

> Because the modification time property on the directory /top/sub changes 
> whenever the file /top/sub/changesdialy.txt changes, every incremental 
> snapshot I make includes an entry for /top/sub to capture the directory 
> property change.

If changesdaily.txt is created with a shell script, then one way of
avoiding the mtime change on the directory is by generating
changesdaily.txt outside the directory and cp'ing it into the directory.

Since cp uses open(2), write(2) and close(2), the inode number of
changesdaily.txt in the directory does not change, so the mtime of the
directory does not change.

If you were to use mv instead, the directory's mtime is updated because
mv is implemented using rename(2) which requires updating the
directory to have a new inode number for changesdaily.txt.

Mathias