bzip2
sourceware.org
What it is
bzip2 is a free data compressor for creating and reading compressed files. It provides command-line tools and supports BZ2 (.bz2), BZ (.bz), TBZ2 (.tbz2), and TBZ (.tbz) formats. The maker says its compression typically comes within 10% to 15% of the best available PPM-family techniques, while running around twice as fast for compression and six times faster for decompression. Its limited media-error recovery may allow undamaged portions of a damaged file to be decompressed. The separate libbzip2 library lets programs read and write .bz2 files or compress data in memory. Command-line flags resemble GNU Gzip's, and the distribution should compile without modification on Unix and Win32 systems. bzip2 dates to 1996 and is open source under a BSD-style license. The official site lists version 1.0.8 as stable and offers source code, not executables. Building has a good chance of success with an ANSI C compiler and at least 8 megabytes of spare memory; the source tarball includes documentation in several formats.
Spec sheet
- Purpose
- bzip2 is a freely available, high-quality data compressor.Read 7 Oct 2026 · sourceware.org
- License
- The maker describes bzip2 as open source under a BSD-style license.Read 7 Oct 2026 · sourceware.org
- Founded
- 1996Read 28 Sep 2026 · sourceware.org
- Compatibility
- Its command-line flags are similar to GNU Gzip's, and the distribution should compile unmodified on Unix and Win32 systems.Read 7 Oct 2026 · sourceware.org
- Compression
- The maker says bzip2 typically compresses files to within 10% to 15% of the best available PPM-family techniques.Read 7 Oct 2026 · sourceware.org
- Current stable version
- The official site lists bzip2 1.0.8 as the current stable version.Read 7 Oct 2026 · sourceware.org
- Documentation
- The source tarball includes pre-built documentation in HTML, PDF, PostScript, and Unix man-page formats.Read 7 Oct 2026 · sourceware.org
- Downloads
- The downloads page provides source code and says no executables are available there.Read 7 Oct 2026 · sourceware.org
- Error recovery
- bzip2 supports limited recovery from media errors and may decompress undamaged parts of a damaged file.Read 7 Oct 2026 · sourceware.org
- Library
- libbzip2 provides an interface for programs to read and write .bz2 files or compress data in memory.Read 7 Oct 2026 · sourceware.org
- Patent statement
- The author says he believes bzip2 does not use patented algorithms but cannot guarantee this because he has not carried out a patent search.Read 7 Oct 2026 · sourceware.org
- Release signing
- The official downloads page says releases are PGP signed and provides a signature file and signing key.Read 7 Oct 2026 · sourceware.org
- Resource requirement
- The downloads page says building has a good chance of success with an ANSI C compiler and at least 8 megabytes of spare memory.Read 7 Oct 2026 · sourceware.org
- Speed
- The maker says bzip2 is around twice as fast at compression and six times faster at decompression than those PPM-family techniques.Read 7 Oct 2026 · sourceware.org
Plans and prices
bzip2 Free Freely available; source code distribution Read 7 Oct 2026 · sourceware.org
Strong points and limits
Strong points
- Free, with command-line tools.
- Supports four listed archive formats.
- Limited recovery may preserve undamaged file portions.
- libbzip2 supports programmatic reading and writing.
Limits
- Downloads provide source code, not executables.
- Archive encryption is not supported.
- Split archives are not supported.
Who it suits
bzip2 suits people who need a free command-line compressor or a library for software that handles .bz2 data. Its source distribution is for users able to build it on Unix/Linux or Win32 systems.
Verdict
bzip2 specifies its formats, library, compatibility, and recovery limits. The downloads are source-only, so users seeking executables will need another route.
Where Specifiction places it
- File Compression Software#13 of 367.8
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