UPX (Ultimate Packer for Executables) is a free, portable, extendable, high-performance executable packer for several different executable formats. It achieves a superb compression ratio and offers very quick decompression.
Your executables endure no memory overhead or other drawbacks due to in-place decompression.
UPX is a copyrighted application distributed under the terms of the GNU General Public License, with special exceptions granting free usage for industrial programs as stated within the UPX License Agreement.
This application makes use of the NRV compression library for compression services. A suitable however considerably less environment-friendly OpenSource implementation is available using the UCL compression library.
- Excellent compression ratio: usually compresses higher than WinZip/zip/gzip, use this application to lower the size of your distribution!
- Very quick decompression: ~10 MB/sec on an ancient Pentium 133, ~200 MB/sec on an Athlon XP 2000+.
- No memory overhead for your compressed executables due to in-place decompression.
- Safe: You can list, check, and unpack your executables. Also, a checksum of each compressed and uncompressed file is maintained internally.
- Universal: UPX can pack several executable formats.
- Portable: UPX is written in portable endian-neutral C++
- Extendable: due to the class layout it’s very simple to add new executable formats or new compression algorithms
- Free: Distributed with full source code under the GNU General Public License v2+, with special exceptions granting free usage for industrial programs as stated within the License Agreement.
Changes in U P X 4.2.1 :
- Linux: /proc/self/exe now is optional
- Windows: use SetFileTime to preserve sub-second file timestamps
- Official Windows builds: revert activeCodePage change introduced in 4.2.0
- Bug fixes
Size: 595 KB