[LBo] Re: warning when unzipping files

[Anita Lewis]

On 04/18/2007 02:02 AM Emen Zhao wrote:
> Hello,
> 
> When I unzip a zip file on my Red Hat Linux box as below, it throws out a
> warning, but the unzip is successful. Does anyone have a clue what causes
> the warning. The zip file was zipped on a windows box using WinZip. I have
> googled the question, but don't find anything useful. Thanks in advance for
> any input.
> 
> $ unzip 1.zip
> Archive:  1.zip
> warning [1.zip]:  455 extra bytes at beginning or within zipfile
>  (attempting to process anyway)
> extracting: 1.txt

I found a note on a manpage by searching on your error message with
http://google.com/linux:

http://www.linuxcommand.org/man_pages/unzipsfx1.html

"Note that self-extracting archives made with unzipsfx are no  more  (or
less)  portable  across  different  operating systems than is the unzip
executable itself.  In general a self-extracting archive made on a
particular Unix system, for example, will only self-extract under the
same flavor of Unix.  Regular unzip may still be used to extract the
embedded  archive  as  with  any normal zipfile, although it will
generate a harmless warning about extra bytes at the  beginning  of  the
 zipfile. Despite this, however, the self-extracting archive is
technically not a valid ZIP archive, and PKUNZIP may be unable to test
or extract  it. This limitation is due to the simplistic manner in which
the archive is created; the internal directory structure is not updated
to reflect the extra bytes prepended to the original zipfile."

That doesn't explain why this happens, but at least it confirms that it
is fairly normal.

Anita