topic Re: zip vs gzip in Operating System - HP-UX

zip vs gzip

Chern Jian Leaw — Fri, 15 Nov 2002 07:55:59 GMT

HI,

I tried doing a zip on a .tar file:
#zip -v file.tar
zip warning: missing end signature--probably not a zip file(did you remember to use binary mode when you transferred it?)

#zip -F file.tar
zip warning: file.tar would be truncated.
Retry with option -qF to truncate, -FF to attempt full recovery.

zip error: Zip file structure invalid(file.tar)

Could someone show me how I could apply zip on a .tar file?

I'm able to do a gzip on a .tar file, but I'm having troubles with zip.

What are the differences between gzip and zip?
Can zip handle .tar files? What are the limitations of zip and gzip?

Could someone kindly help me out.
Thanks

Re: zip vs gzip

Jean-Louis Phelix — Fri, 15 Nov 2002 08:10:19 GMT

hi,

What is zip on hp-ux ? I only know gzip. The message you give seems to be an uncompression message rather than a compression message. Where did you find it ?

Regards

Re: zip vs gzip

Stefan Farrelly — Fri, 15 Nov 2002 08:11:51 GMT

Try;
cat file.tar | zip > file.zip

zip isnt commonly used. HP's uses compress, the newew gzip (better compression) and the even newer bzip2 (even better compression). gzip is a bit more robust - you can gzip anything (gzip file, or cat file | gzip > newfile, or gunzip file) but zip is really for windows/PC's. Winzip on windows/PC's understands tar files or gzip files perfectly so there is really no need to use zip. We dont.

Re: zip vs gzip

Chern Jian Leaw — Fri, 15 Nov 2002 08:29:36 GMT

Jean-Louise,

I'm executing zip on a HPUX 10.20, which I placed it on /usr/local/bin/. The zip version which I'm running is zip 2.1

Any ideas?

Thanks

Re: zip vs gzip

T G Manikandan — Fri, 15 Nov 2002 09:09:53 GMT

#tar cf - . | zip test -

This should create a zip file called test

ALso you can try doing a

#zip test1 file.tar

This should create a test1.zip

Revert

Re: zip vs gzip

Bill McNAMARA_1 — Fri, 15 Nov 2002 09:16:36 GMT

you probably got zip from http://hpux.cs.utah.edu/ as it is not standard unix.
I recommend gzip as winders will be able to decompress it. You can also get better compression with
gzip -9 file

Later,
Bill

Re: zip vs gzip

H.Merijn Brand (procura — Fri, 15 Nov 2002 09:27:42 GMT

Forget both zip and gzip. Use bzip2. For 10.20 binaries are available on https://www.beepz.com/personal/merijn

For tar archives with source files, bzip2 compresses 30% better than gzip -9

Original URL's:

bzip2: http://sources.redhat.com/bzip2/
gzip: ftp://download.xs4all.nl/pub/mirror/gnu/gzip/
zip: http://www.info-zip.org/pub/infozip/
unzip: http://www.info-zip.org/pub/infozip/
zlib: http://www.gzip.org/zlib/

.tar.gz .tar.bz2 .tar.Z .zip .tgz .tbz are all recognized by powerarchiver on the PC (http://www.powerarchiver.com)

Re: zip vs gzip

Chern Jian Leaw — Fri, 15 Nov 2002 10:07:56 GMT

Is there a performance issue when using gzip over zip for compressing large files?

Re: zip vs gzip

Chern Jian Leaw — Fri, 15 Nov 2002 10:32:09 GMT

Procura,
Thanks for those useful links. But if I'm not mistaken, zlib uses the gzip compression algorithm, hence, does zlib has better compression rate compared to gzip for large filesystems i.e > 2GB?

thanks

Re: zip vs gzip

H.Merijn Brand (procura — Fri, 15 Nov 2002 11:06:16 GMT

Thanks for those useful links. But if I'm not mistaken, zlib uses the gzip compression algorithm, hence, does zlib has better compression rate compared to gzip for large filesystems i.e > 2GB?

The other way round. gzip uses zlib :)
zlib has been updated not so long ago because of some security issues

bzip has a much better compression algorithm, in any case for non-binary files

AFAIK zip/unzip is not actively maintained, and will thus not have the highest compression rate

I'm open for corrections regarding this info :)

[points]