UnZip 6.0

The Third Most Portable Program in the World! *

UnZip is an extraction utility for archives compressed in .zip format (also called "zipfiles"). Although highly compatible both with PKWARE's PKZIP and PKUNZIP utilities for MS-DOS and with Info-ZIP's own Zip program, our primary objectives have been portability and non-MSDOS functionality.

UnZip will list, test, or extract files from a .zip archive, commonly found on MS-DOS systems. The default behavior (with no options) is to extract into the current directory (and subdirectories below it) all files from the specified zipfile. A companion program, Zip, creates .zip archives; both programs are compatible with archives created by PKZIP and PKUNZIP for MS-DOS, but in many cases the program options or default behaviors differ. (For example, UnZip recreates the stored directory structure by default; PKUNZIP unpacks all files in the current directory by default.)

Contents of This Page:

• Latest Release
• Future Plans
• Downloads
• Other Stuff

Latest Release

New features in UnZip 6.0, released 20 April 2009:

• Support PKWARE ZIP64 extensions, allowing Zip archives and Zip archive entries larger than 4 GiBytes and more than 65536 entries within a single Zip archive. This support is currently only available for Unix, OpenVMS and Win32/Win64.
• Support for bzip2 compression method.
• Support for UTF-8 encoded entry names, both through PKWARE's "General Purpose Flags Bit 11" indicator and Info-ZIP's new "up" unicode path extra field. (Currently, on Windows the UTF-8 handling is limited to the character subset contained in the configured non-unicode "system code page".)
• Added "wrong implementation used" warning to error messages of the MSDOS port when used under Win32, in an attempt to reduce false bug reports.
• Fixed "Time of Creation/Time of Use" vulnerability when setting attributes of extracted files, for Unix and Unix-like ports.
• Fixed memory leak when processing invalid deflated data.
• Fixed long-standing bug in unshrink (partial_clear), added boundary checks against invalid compressed data.
• On Unix, keep inherited SGID attribute bit for extracted directories unless restoration of owner/group id or SUID/SGID/Tacky attributes was requested.
• On Unix, allow extracted filenames to contain embedded control characters when explicitly requested by specifying the new command line option "-^".
• On Unix, support restoration of symbolic link attributes.
• On Unix, support restoration of 32-bit UID/GID data using the new "ux" IZUNIX3 extra field introduced with Zip 3.0.
• Support for ODS5 extended filename syntax on new OpenVMS systems.
• Support symbolic links zipped up on VMS.
• On VMS (only 8.x or better), support symbolic link creation.
• On VMS, support option to create converted text files in Stream_LF format.
• New -D option to suppress restoration of timestamps for extracted directory entries (on those ports that support setting of directory timestamps). By specifying "-DD", this new option also allows to suppress timestamp restoration for ALL extracted files on all UnZip ports which support restoration of timestamps. On VMS, the default behaviour is now to skip restoration of directory timestamps; here, "--D" restores ALL timestamps, "-D" restores none.
• On OS/2, Win32, and Unix, the (previously optional) feature UNIXBACKUP to allow saving backup copies of overwritten files on extraction is now enabled by default.

For the UnZip 6.0 release, we want to give special credit to Myles Bennet, who started the job of supporting ZIP64 extensions and Large-File (> 2GiB) and provided a first (alpha-state) port.

Future Plans

The next major release will be version 6.1.

It is questionable whether there will ever be a subsequent major release, but on the off-chance that there is, it will probably be version 7.0, perhaps with a much-improved and unified DLL interface and possibly better file system support for the MVS and VM/CMS ports, assuming that doesn't happen sooner. And then perhaps version 8.0 will be released, with full filter support (that is, able to read and extract a zipfile from standard input like fUnZip does now), but now we're really dreaming. While we're at it, though, a tcl/tk or Python/PIL graphical interface might be nice--but see the related-links section for a pointer to TkZip, which already exists (and has for a long time).

Downloads

Ready-to-run binary versions of UnZip are available for numerous platforms and operating systems, but for most systems, only older binaries are available. The three primary CTAN sites (and their many mirrors) contain a snapshot of these binaries, current as of roughly 2004 (i.e., UnZip 5.51 and Zip 2.3 timeframe):

• tug.ctan.org (US) [FROZEN]
• ftp.tex.ac.uk (UK) [FROZEN]
• ftp.dante.de (Germany) [FROZEN]

Here's a quick guide to the directory structure of the old ftp site:

As of 2009, the latest sources and binaries for Zip, UnZip, WiZ and MacZip (including encryption code) are available at ftp.info-zip.org and Info-ZIP's SourceForge site.

Other Stuff

Technical information on zipfiles and other assorted Info-ZIP documentation is available from:

• www.info-zip.org (Kentucky, US) or local mirror

Technical information and documentation for deflate/inflate and zlib are available from:

• zlib home page

Further information on where to (possibly) find Info-ZIP stuff is available in:

• the Info-ZIP "WHERE" file (ASCII text)

Information about commercial use, modification and redistribution of Zip, UnZip, WiZ and MacZip is available in:

• the Info-ZIP license

It's basically BSD-like, but note that there may still be a few remaining files in some of the packages that are covered by different licenses.

Return to the Info-ZIP Home Page.