Author Topic: UPX is a free, portable, extendable, high-performance executable packer  (Read 2303 times)

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UPX - the Ultimate Packer for eXecutables, is a free, portable, extendable, high-performance executable packer for several executable formats.  Versions for Windows, Linux, Atari TOS-MiNT, and DOS (FreeDOS) platforms. The term UPX is a shorthand for the Ultimate Packer for eXecutables.

For the Mac OS X port of UPX: go HERE: 
UPX - Ultimate Packer for eXecutables universal binary for MacOSX 10.4 or later

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                    The Ultimate Packer for eXecutables
   Copyright (c) 1996-2018 Markus Oberhumer, Laszlo Molnar & John Reiser



Welcome to UPX !

Please don't forget to read the file LICENSE - UPX is distributed
under the GNU General Public License (GPL) with special exceptions
allowing the distribution of all compressed executables, including
commercial programs.


UPX is an advanced executable file compressor. UPX will typically
reduce the file size of programs and DLLs by around 50%-70%, thus
reducing disk space, network load times, download times and
other distribution and storage costs.

Programs and libraries compressed by UPX are completely self-contained
and run exactly as before, with no runtime or memory penalty for most
of the supported formats.

UPX supports a number of different executable formats, including
Windows 95/98/ME/NT/2000/XP/CE programs and DLLs, DOS programs,
and Linux executables and kernels.

UPX is free software distributed under the term of the GNU General
Public License. Full source code is available.

UPX may be distributed and used freely, even with commercial applications.
See the UPX License Agreement for details.

UPX is rated number one in the well known Archive Comparison Test.

UPX aims to be Commercial Quality Freeware.


'upx program.exe' will compress a program or DLL. For best compression
results try 'upx --brute program.exe'.

Please see the file UPX.DOC for the full documentation. The files
NEWS and BUGS also contain various tidbits of information.


UPX achieves an excellent compression ratio and offers very fast decompression. Your executables suffer no memory overhead or other drawbacks for most of the formats supported, because of in-place decompression.

UPX strengths in a nutshell:

    excellent compression ratio: typically compresses better than WinZip/zip/gzip, use UPX to decrease the size of your distribution!
    very fast decompression: ~10 MB/sec on an ancient Pentium 133, ~200 MB/sec on an Athlon XP 2000+.
    no memory overhead for your compressed executables because of in-place decompression.
    safe: you can list, test and unpack your executables. Also, a checksum of both the compressed and uncompressed file is maintained internally.
    universal: UPX can pack a number of executable formats.
    portable: UPX is written in portable endian-neutral C++.
    extendable: because of the class layout it's very easy to add new executable formats or new compression algorithms.
    free: UPX is distributed with full source code under the GNU General Public License v2+, with special exceptions granting the free usage for commercial programs as stated in the UPX License Agreement.

You probably understand now why we call UPX the "Ultimate Packer for eXecutables".


UPX comes with ABSOLUTELY NO WARRANTY; for details see the file LICENSE.

Having said that, we think that UPX is quite stable now. Indeed we
have compressed lots of files without any problems. Also, the
current version has undergone several months of beta testing -
actually it's almost 8 years since our first public beta.

This is the first production quality release, and we plan that future
releases will be backward compatible with this version.

Please report all problems or suggestions to the authors. Thanks.
« Last Edit: December 07, 2018, 09:40:59 AM by Software Santa »


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