Rationale behind naming "dot d" (.d) directories

[Ryan Schmidt]

On Apr 22, 2009, at 23:20, Jordan K. Hubbard wrote:

> On Apr 22, 2009, at 8:09 PM, Ryan Schmidt wrote:
>
>> Does anyone know the history behind the ".d" naming convention on  
>> some directories?
>>
>> For example, /etc/rc.d or ${prefix}/etc/bash_completion.d. I seem  
>> to understand how these directories are used, but what does the  
>> ".d" mean?
>
> The history was pretty simple.  When we had a file called /etc/foo,  
> which we later to split into a directory full of individual one- 
> entry-per-file records rather than the previous "all records in a  
> single file", we would rename /etc/foo to /etc/foo.d to denote the  
> switch.

Thanks for the explanation. That makes sense, as it avoids the  
problems of an object with a given name changing from a file to a  
directory from one release to the next.

The reason I ask is for a change I'm working on for the php5  
extension ports. Currently, ports like php5-memcache just print a  
message telling the user to add these lines to their php.ini:

extension_dir=/opt/local/lib/php/extensions/no-debug-non-zts-20060613
extension=memcache.so

But php can be configured to look for additional ini files in a  
certain directory. So I would like to modify the php5 port to do  
this, and then modify ports like php5-memcache to just install a file  
like e.g. memcache.ini which contains these lines. Then the extension  
will automatically be loaded and the user won't have to do it manually.

Currently, the php.ini is in /opt/local/etc. This is a little out in  
the open and I would like to move it into a directory of its own,  
probably named for the port, so, say, /opt/local/etc/php5. This would  
also be a step toward allowing php4 and php5 (and a hypothetical  
future php6) to be installed simultaneously which is desirable.

Now I need a directory in which php5 extension ports will install  
their small additional .ini files. I don't think it should be the  
same /opt/local/etc/php5 directory because php is set up to first  
look for its one true php.ini and then load all the additional ini  
files in a directory; this might cause php.ini to be parsed twice,  
which is at best wasteful and at worst could cause problems. Order  
may also be important so I would like to load php.ini first, then the  
other files. So for the directory name, should I use /opt/local/etc/ 
php5.d? /opt/local/etc/php5/php.d? Or forget about the whole .d thing  
and make it /opt/local/etc/php5/extra (which would be similar to /opt/ 
local/apache2/conf/extra)? Other suggestions?


> Don't forget, /etc/rc used to be a single file...

And indeed I wasn't looking: it *is* a single file, even on Leopard.