Very Computer

I need to compress a directory for archiving purposes,
but before I can do that I need to know how much space
it will occupy.  Is there a way I can find out how
much space it will take to tar | gzip it without
having to actually create the compressed file?  I
thought perhaps about

        tar -cvf - . | gzip - > /dev/null

but I don't know if that would work.  Any comments via
email would be appreciated.

/* count.c */
#include <stdio.h>
main()
{
  int c,i;
  i = 0;
  while ( (c=getchar())!=EOF )  i++;
  printf ( "%d/n", i );

Quote:}

P.s. there is a standart unix utility that counts it's stdio size,
but I can't remember it's name ...

tar cf ... | gzip - | wc -c

(-c tells it to output # of bytes).

Your program won't work on files larger than MAXINT bytes; using longs
would be better, but wc is probably the best solution.

Cordially,

  Sumner

Please don't CC: postings to me, my mailbox is already full enough.

Quote:>I need to compress a directory for archiving purposes,
>but before I can do that I need to know how much space
>it will occupy.  Is there a way I can find out how
>much space it will take to tar | gzip it without
>having to actually create the compressed file?

the -9 parameter to gzip *does* make a difference, in my experience.
tar, by default, seems not to use it; i've lately taken to manually
gzipping .tar files.
--
        "...Everybody got this broken feeling
         like their father or their dog just died..."
                                                        - Leonard Cohen

xemacs.tar.gz   16MB (gzip -9)
xemacs.tar.bz   12MB (bzip)

That's a significant savings.

Cordially,

  Sumner

--
Respond by post or email, but please don't CC: postings to me; my mailbox
is already quite full.

...
: xemacs.tar.gz   16MB (gzip -9)
: xemacs.tar.bz   12MB (bzip)

try bzip -9 ;)

--

   Supelec - Residence des eleves - 91192 Gif sur Yvette - 01 69 85 50 16
                   http://hal.rez-gif.supelec.fr/~eric

[...]

Quote:>The -9 makes an almost insignificant difference on most files.  If you
>really need extra compression, use a better compression program (like
>bzip, available at sunsite).  

now if only i could hack GNU tar into recognizing it...
--
        "...Everybody got this broken feeling
         like their father or their dog just died..."
                                                        - Leonard Cohen