[basedir-spec] What exactly is $XDG_DATA_HOME for ?

[Thomas Leonard]

On Tue, 27 May 2008 23:12:55 +0200, thibaut bethune wrote:
[...]
> I thought that $XDG_CONFIG_HOME was for configuration files and that
> $XDG_DATA_HOME was for data. For instance, in the particular case of
> Transmission (a BitTorrent client http://www.transmissionbt.com/ ) which
> creates several folders in home directory :
>     * $HOME/.transmission/cache/
>     * $HOME/.transmission/gtk/
>     * $HOME/.transmission/torrents/
>     * $HOME/.transmission/stats.bench
> and where $HOME/.transmission/torrents/ has information about files
> currently downloaded, i thought these informations were date that should
> be in $XDG_DATA_HOME.

The spec says:

"There is a single base directory relative to which user-specific data 
files should be written. This directory is defined by the environment 
variable $XDG_DATA_HOME."

I think "user-specific data" is very confusing here.

However, the default user (~/.local/share) and system (/usr/local/share/:/
usr/share/) paths indicate what it is really for. In other words, it is 
for things that could reasonably go in /usr/share.

Or, for what would result if you did:

  $ ./configure --prefix=$HOME/.local/ && make install

> But Transmission developer (Charle at
> http://trac.transmissionbt.com/ticket/684 ) has understood (concerning
> files in $HOME/.transmission/torrents/ ) that "the intention of
> XDG_DATA_HOME vs XDG_CONFIG_HOME is that the former should only be
> written to when installing software. That way the directory is
> relatively constant, which makes backups easier for system
> administrators.

Correct.

> By contrast, XDG_CONFIG_HOME is where all the
> frequently-changed or short-term files go. Given the short-term nature
> of .torrent files, IMO they're a better fit for XDG_CONFIG_HOME. They
> *definitely* aren't files written once when installing software."

Some of these should probably go in $XDG_CACHE_HOME instead (things that 
could be downloaded again easily, for example).


-- 
Dr Thomas Leonard		http://rox.sourceforge.net
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