Changing the name of a compressed file

[Aki Tuomi]

> On June 10, 2017 at 5:58 AM Peter West <lists at pbw.id.au> wrote:
> 
> 
> Concerning Maildir, the wiki page on compression has this:
> 
> All mails must have ,S=<size> in their filename where <size> contains the original uncompressed mail size, otherwise there will be problems with quota calculation as well as other potential random failures. Note that if the filename doesn’t contain the ,S=<size> before compression, adding it afterwards changes the base filename and thus the message UID. The safest thing to do is simply to not compress such files.
> 
> Further down on the same page is this:
> 
> If the file does exist, rename() (mv) the compressed file over the original file.
> 	• Dovecot can now read the file, but to avoid compressing it again on the next run, you'll probably want to rename it again to include e.g. a "Z" flag in the file name to mark that it was compressed (e.g. 1223212411.M907959P17184.host,S=3271:2,SZ).
> 
> These comments seem to contradict each. Or is there a difference between adding the size specifier to the filename and adding a Z flag to the end of the file name?
> 
> --
> Peter West
> pbw at pbw.id.au
> And the great throng heard him gladly.
>

Keyword is 'base filename'. From the wiki, "The standard filename definition is: "<base filename>:2,<flags>".". Z is a flag.

Aki