[Bug-tar] Re: Auto-exclude of cache directories for tar, cpio

[Paul Eggert]

Bryan Ford <address@hidden> writes:

>       http://www.brynosaurus.com/cachedir/

That proposal uses a file name ".IsCacheDirectory" that is not
portable to traditional Unix file systems that have a 14-byte limit on
file names.  Also, some non-Unix file systems have trouble
distinguishing case.  So you might want to use a name like
".iscachedir" instead.

The "find" command used as an example doesn't check for the required
MD5 signature.  Most likely other software will do the same.  This
suggests that the signature isn't needed.  Perhaps just the existence
of the file would be enough.

The proposal doesn't talk about symbolic links; you probably need to
address that issue while you're at it.  For example, can
".IsCacheDirectory"/".iscachedir" be a symbolic link to a file?  a
dangling symbolic link?

> I'd also like to get a sense of whether you might be willing, once the 
> proposal solidifies and is supported by more applications, to add a simpler, 
> user-friendly option to tar and/or cpio such as "--exclude-caches", which 
> would automatically look for cache tags and Do The Right Thing.

That sounds reasonable to me.  (If you write the code it would be even
more reasonable.....)