On 20/10/2015 11:21, Corinna Vinschen wrote:
> On Oct 19 19:21, Achim Gratz wrote:
>> Corinna Vinschen writes:
>>> I agree.  Actually, considering that the info files are stored in just a
>>> single well-known directory, /usr/share/info(*), and further considering
>>> that updated files are rewritten when overwritten, shouldn't it be entirely
>>> sufficient if the update_info_dir script performs a simple test like this:
>>>
>>> - Does /usr/share/info/dirs exist?
>>>
>>>    No -> run install-info
>>>
>>>    Yes -> Is /usr/share/info/dirs mtime < /usr/share/info mtime?
>>>
>>>           No -> Do nothing
>>>
>>> 	 Yes -> run install-info

So, this is actually quite straightforward to write, and 
/etc/postinstall/0p_update-info-dir.sh becomes the attached.

>> Can this be relied on for all possible file systems?
>
> Not on FAT.  But then again, FAT is not really a filesystem, rather just
> a failed try.

But yes, this does nothing useful if /usr/share/info is on a FAT 
filesystem, as the mtime doesn't change.