On Saturday, February 1, 2020 at 11:49:53 PM UTC-5, heiphohmia wrote:
>
> > Could .gz or .bz2 be used instead?  I think those are stable.


I tested it, and tar.bz2 seems stable but tar.gz changes its md5sum each 
time I run tar -czf.  That is very surprising because I'm almost positive 
that tar.gz was (empirically) stable a few years ago.  I wonder whether we 
can depend on tar.bz2 being stable in the long run.

Norm
 

>
> Either of those would be great. Typically, bzip2 wins on compression and 
> gzip 
> on speed. In this case, bzip2 is probably a good choice. 
>
> In the off chance it's helpful, here are the standard command line 
> invocations 
> on unix for creating bzip2 and gzip archives of some directory: 
>
>     $ tar -cjf new-bzip2-archive.tar.bz2 path/to/contents 
>     $ tar -czf new-gzip-archive.tar.gz path/to/contents 
>

>
> The -c flag "creates" an archive, the -j and -z flags compress with bzip2 
>  and gzip respectively. The -f flag specifies the archive path. 
>
> And just in case the use of tar seems mysterious, the reason we need it 
> here is 
> because bzip2 and gzip are simply compression formats, meaning they only 
> work 
> on single files. So we use tar to first "archive" a collection of paths 
> into a 
> single file and compress the result. This is a common enough operation 
> that tar 
> simply provides convenience flags that do the wrapping for us. 
>

-- 
You received this message because you are subscribed to the Google Groups 
"Metamath" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To view this discussion on the web visit 
https://groups.google.com/d/msgid/metamath/f9e39cab-e9ca-4cc1-bb5d-90e7991f2551%40googlegroups.com.

Reply via email to