7Z to TGZ Converter

What is 7Z to TGZ Conversion?

Converting 7Z to TGZ is the transition to the most widespread archive format of the Unix ecosystem. The TGZ extension is shorthand for tar.gz: source files are first collected into a TAR container that preserves the directory hierarchy and POSIX metadata, then the resulting stream is compressed with the GZIP algorithm. The GZIP algorithm was developed by Jean-Loup Gailly and Mark Adler in 1992 as a free alternative to compress, and today GZIP remains one of the most widely used compressors in the world.

GZIP is built on the DEFLATE algorithm, which combines LZ77 dictionary compression with Huffman coding. The dictionary size in DEFLATE is only 32 KB, which prevents finding distant repetitions like LZMA2 does in 7Z. In return, however, GZIP delivers exceptional speed: it compresses tens of times faster than BZIP2 and hundreds of times faster than XZ at maximum levels, while decompression runs at virtually disk read speed. This property has made TGZ the standard format for distributing source code, deploying applications, and running operational backups.

When converting 7Z to TGZ, the source archive contents are decompressed from LZMA2 blocks into the original files, packed into a standard TAR stream with Unix attributes restored, and the stream is then passed through GZIP. The result is slightly larger than the 7Z, but opens on practically any system in the world with a single utility call.

Technical Differences Between 7Z and TGZ Formats

Compression Algorithms

7Z is built on LZMA2, a dictionary algorithm with range coding. A large adaptive dictionary up to 1 GB searches for matches at huge distances, delivering high compression ratios. Additional filters (BCJ for executables, delta encoding for media) further increase efficiency.

GZIP uses DEFLATE, a combination of LZ77 with a 32 KB dictionary and adaptive Huffman coding. The algorithm works in blocks: each block is compressed with its own Huffman table optimized for local data statistics. DEFLATE deliberately sacrifices compression ratio for speed and low memory consumption.

Comparison Table

Real Compression Ratios

Size comparison for typical data sets:

TGZ is usually 30-60% larger than 7Z for text data, but opens on any Unix system with a single tar xzf command without installing additional tools.

When 7Z to TGZ Conversion is Necessary

Source Code Distribution

TGZ is the undisputed standard for distributing source code in the Unix community:

• Release tarballs - projects using GNU autotools, CMake, Meson publish releases as tar.gz with a version number in the name.
• Git repository archives - GitHub, GitLab, and Bitbucket generate tar.gz files on demand with branch or tag content.
• CPAN, PyPI sdist - Perl and Python modules in source form are distributed as tar.gz packages.
• FreeBSD ports distributions - the ports system builds programs from tar.gz files downloaded from upstream servers.
• Archive snapshots - historical program releases are stored as TGZ in GNU, SourceForge, and Savannah archives.

Fast Decompression Matters More Than Size

Scenarios where speed matters more than size:

• Application deployment - rolling out updates to servers where every minute of downtime is expensive. TGZ extraction is limited only by disk speed.
• Container images - Docker layers and Kubernetes manifests often include TGZ archives extracted at container startup.
• CI/CD cache - build artifacts in Jenkins, GitLab CI, and GitHub Actions are passed as tar.gz due to fast processing.
• Database backups - incremental backups are made frequently, compression time adds up to days over a month, and GZIP is irreplaceable here.

POSIX Metadata Preservation

Since TGZ is TAR with GZIP compression, it inherits all of TAR's capabilities for working with Unix attributes:

• chmod permissions - file and directory modes are saved in octal form in each record header.
• UID/GID owners - user and group identifiers are written in headers, and through USTAR also their names.
• Timestamps - mtime in each record, with PAX extensions adding atime and ctime.
• Symlinks and hardlinks - preserved with target path references, without duplicating content.
• Special files - block and character devices, FIFOs, and sockets are transferred as corresponding record types.

Minimal Resource Requirements

GZIP is one of the most economical compressors:

• Memory at compression - about 1-2 MB regardless of input data size.
• Memory at decompression - 32 KB for the dictionary plus buffers.
• Compatibility with embedded systems - TGZ opens even on routers with busybox, IoT devices, and media players.
• Parallel processing - the pigz utility compresses in multiple threads, accelerating the process on modern CPUs.

This is especially important for memory limited servers and embedded systems where LZMA2 would be excessive.

Conversion Process: What Happens to the Archive

Transformation Stages

1. Reading and decompressing 7Z - the archive header is analyzed, LZMA2 blocks are decompressed into the original file bytes.

2. File tree reconstruction - names, paths, and POSIX attributes are restored into a directory hierarchy with permissions, owners, and timestamps.

3. TAR stream formation - each file is preceded by a 512 byte header with metadata, after which the content is written aligned to a 512 byte boundary.

4. DEFLATE application - the TAR stream is split into blocks, each going through LZ77 dictionary search with a 32 KB window.

5. Huffman coding - found literals and back references are encoded with dynamic Huffman tables optimized for each block.

6. GZIP wrapper - the compressed stream is preceded by a GZIP header with the magic number, modification time, flags, and finalized with CRC-32 and the size of uncompressed data.

7. Final file write - the result is saved with the .tar.gz or .tgz extension.

What is Preserved and What Changes

Preserved:

• File and directory names with full paths (including Unicode)
• Content of all files (byte for byte)
• Directory structure of any depth
• Modification timestamps
• Permissions, owners, groups (if present in 7Z)

Changed:

• Compression algorithm (LZMA2 replaced with DEFLATE)
• Container (proprietary 7Z replaced with TAR)
• Archive size (typically 30-60% larger than 7Z for text)
• Checksum (CRC-64 in 7Z is replaced with CRC-32 in GZIP)

Not transferred:

• Encryption (the GZIP standard does not have it)
• Solid compression mode (GZIP compresses as a stream)
• Random access to files inside the archive (full extraction is required)

Comparing TGZ with Other Formats

TGZ vs TBZ2

TGZ is chosen for speed, TBZ2 for compactness.

TGZ vs TXZ

TXZ is more compact, TGZ is more universal.

TGZ vs ZIP

ZIP is better for mixed environments, TGZ for Unix specific tasks.

TGZ Compatibility and Support

Operating Systems

TGZ is the most universally supported Unix format:

• Linux - the tar and gzip utilities are present in any distribution, from full server systems to minimalistic embedded BusyBox builds.
• macOS - bsdtar in the system handles tar.gz without additional installations: the tar xzf command works out of the box.
• FreeBSD, OpenBSD, NetBSD - tar and gzip are part of base installations of all BSD systems.
• Windows - since Windows 10 1803, the system tar command understands gzip archives. For graphical work, any archiver (7-Zip, WinRAR, PeaZip) opens tgz with a double click.
• Android and iOS - third party file managers with archive support handle tar.gz without additional modules.
• Embedded systems - OpenWRT routers, IoT devices, and media players extract TGZ with native tools.

History and Development of GZIP

GZIP has a rich history:

• 1992 - Jean-Loup Gailly and Mark Adler release the first version of gzip in response to patent restrictions on the compress format.
• 1996 - publication of RFC 1952 describing the GZIP file format as an open standard.
• 1999 - DEFLATE becomes part of the HTTP specification (RFC 2616) for compressing web traffic.
• 2000s - GZIP becomes the standard for source code tarballs in all significant Unix projects.
• 2010s - the appearance of pigz (parallel gzip) accelerates compression on multi core CPUs.
• Today - GZIP remains the most widespread compressor in the world, supported on billions of devices.

Programming Languages

GZIP and TAR support is built into standard libraries:

This allows automating work with TGZ in scripts, server applications, and web services.

Limitations and Alternatives

When TGZ is Not Optimal

• Very large collections of uniform content - the gain from LZMA2 in 7Z or XZ can be tens of times.
• Long term archives - where saving space matters more than speed, TXZ is preferable.
• Highly redundant text data - BZIP2 gives a more compact result for books and source code.

Alternative Scenarios

• 7Z to TXZ - maximum LZMA2 compression in a Unix wrapper for long term storage.
• 7Z to TBZ2 - strong BZIP2 compression for text, classic of Unix distributions.
• 7Z to TAR - clean container without compression for further processing.
• 7Z to ZIP - for sending to Windows users.

Conversion to TGZ is justified when the most compatible Unix format with fast decompression and minimal resource requirements is needed.