ZIP to TAR Converter

What is ZIP to TAR Conversion?

Converting ZIP to TAR means repacking archive contents from a DEFLATE compression format into a pure Unix container without compression. File names, folder structure, and the contents of each file are fully preserved, but the philosophy of storage changes dramatically. ZIP, developed by Phil Katz in 1989, combines archiving and compression into a single format using the DEFLATE algorithm. TAR (Tape ARchive), introduced in 1979 in Unix, is purely an archival container that joins files into a single stream without any compression while preserving every nuance of Unix file system metadata.

The main reason for converting ZIP to TAR is moving to a Unix environment, where TAR is the native archival format. Unlike ZIP, which was originally designed for DOS and Windows, TAR fully preserves POSIX attributes: access permissions (rwx for owner, group, and others), user and group identifiers (UID/GID), symbolic and hard links, special files. This is critical when transferring source code, software distributions, development packages, and any data requiring correct permissions after extraction.

During conversion, the contents of the ZIP archive are fully extracted, after which files are placed into a TAR container with Unix attributes restored. The resulting TAR will be significantly larger than the source ZIP, typically 2-10 times for text data, since TAR applies no compression. This is offset by ideal integration with Unix tooling and the option to apply a separate compression algorithm later (gzip, bzip2, xz) when needed.

Technical Differences Between ZIP and TAR Formats

Approach to Archiving

ZIP is a container with integrated compression. Each file is compressed by the DEFLATE algorithm independently of the others, then written to the archive with a local header. At the end of the file is a central directory, an index with information about all entries. This structure allows instant access to any file without extracting its neighbors.

TAR is a pure archive format without compression. Files are written sequentially in 512 byte blocks with a header before each file containing metadata. A TAR archive is literally files glued together with headers. There is no index or central directory, which simplifies streaming processing but requires reading the entire archive to extract a single file.

Capability Comparison Table

Archive Sizes: Real Examples

Size comparison for typical data sets:

Since TAR does not compress data, the archive size is practically equal to the sum of all file sizes plus a small header overhead (usually 1-5%). For already compressed data such as JPG or MP4, the difference between ZIP and TAR is minimal because DEFLATE is already unable to compress entropy rich files.

When ZIP to TAR Conversion is Necessary

Moving Data to Unix Environments

TAR is the standard format of the Unix world, and many tasks require it specifically:

• Linux server deployments - system administrators prefer TAR when working with configurations, web projects, and deployment packages.
• Source code transfer - C, C++, Python projects for Unix developers traditionally ship in the TAR family of formats.
• Server to server data migration - syncing between Linux machines via rsync, scp, sftp is more convenient with TAR archives.
• Container preparation - building Docker images often involves working with TAR layer archives.
• Embedded system deployment - firmware and images for embedded Linux devices use TAR as the primary format.

Further Processing with Specialized Tools

TAR is convenient as an intermediate format for subsequent operations:

• Applying different compression algorithms - after converting to TAR you can compress the archive with gzip, bzip2, xz, or zstd depending on the task.
• Splitting into volumes of arbitrary size - the split utility divides TAR into pieces of any size for writing to different media.
• External encryption - GnuPG, OpenSSL, AGE apply to a TAR archive like any other file.
• Pipeline transfer in shell - TAR integrates beautifully into Unix command line pipelines.
• Tape storage - the original purpose of the format, still relevant for corporate backup systems.

Preserving Unix Specific Metadata

Some data types require exact preservation of file system attributes:

• System configurations - files in /etc, /var, /opt with different owners and access rights.
• Web servers - Apache, Nginx files with proper permissions for security (such as 644 for files and 755 for directories).
• Databases - dump files for PostgreSQL, MySQL preserving postgres or mysql ownership.
• User profiles - contents of /home/user with private 700 permissions on hidden directories.
• Server backups - full partition snapshots with complete POSIX metadata preservation.

Creating an Intermediate Uncompressed Image

Sometimes an uncompressed format is preferable:

• Archives for deduplication - corporate storage systems with block deduplication work more effectively on uncompressed data.
• Writing to media with hardware compression - LTO tape drives apply their own compression algorithm and do not need pre compression.
• Analyzing archives without extraction - on uncompressed TAR you can run grep, search by file names, and quickly preview contents.
• Fast writing to slow media - compression time on weak hardware can exceed the gain from size reduction.

Conversion Process: What Happens to the Archive

Transformation Stages

1. Reading the ZIP central directory - the list of all archive files is extracted with names, sizes, checksums, and metadata.

2. DEFLATE decompression - each file's contents are decoded into the original bytes. This stage is fast and undemanding for memory.

3. Restoring file structure - files are temporarily placed in the folder hierarchy according to original paths. Timestamps are restored.

4. Attribute conversion - DOS attributes from ZIP (read only, hidden, system) are converted to Unix attributes with default access rights (typically 644 for files and 755 for directories).

5. Writing TAR blocks - each file is written with a 512 byte header containing name, size, permissions, timestamps, and checksum. The header is followed by file content padded with zeros to a multiple of 512 bytes.

6. Archive finalization - two empty blocks (1024 bytes of zeros) are written at the end of TAR to signal the end of the archive.

What is Preserved and What Changes

Preserved:

• File names and extensions (including Unicode characters via the PAX extension)
• Folder and subfolder structure
• File contents (byte for byte)
• Modification timestamps
• Relative file paths

Changed:

• Archive size (grows 2-10x for compressible data)
• Storage structure (no compression and no central directory)
• Checksums (CRC-32 in ZIP replaced by simple sum in the TAR header)
• File attributes (DOS flags converted to Unix permissions)

May be lost:

• Encryption (TAR in pure form does not support passwords)
• Digital signatures on the ZIP archive
• Comments to the archive and individual files
• Exact DOS attributes that have no Unix counterpart

Comparing TAR with Other Formats

TAR vs ZIP

Fundamentally different approaches to archiving:

TAR is more convenient for Linux system administration, ZIP for wide distribution.

TAR vs CPIO

CPIO is another Unix archive format.

TAR dominates general use, CPIO remains in specific niches.

TAR vs Modern Formats

TAR appeared before the era of personal computers and retains an archaic structure. Modern formats (DAR, AR, PAX) offer improvements:

• Random access - DAR maintains a catalog for quick extraction of individual files.
• Extended attributes - the PAX format stores ACL, xattr, and other metadata.
• Integrity - built in checksums and block recovery.

Despite its age, TAR remains the standard thanks to universal compatibility.

TAR Compatibility and Support

Operating Systems

TAR is supported by all Unix like systems natively:

• Linux - the tar utility ships with every distribution as part of the coreutils package. Supports all compression variants through -z, -j, -J, --zstd flags.
• macOS - the tar command is available in Terminal out of the box. Finder opens TAR on double click via Archive Utility.
• FreeBSD, OpenBSD, NetBSD - BSD-tar is part of the base system, supporting all standard operations.
• Solaris, AIX, HP-UX - commercial Unix variants have native TAR implementations.
• Windows - since Windows 10 1803 (2018) the tar.exe command ships with the system. Graphically TAR opens through 7-Zip, WinRAR, PeaZip, Bandizip.
• Android - file managers ZArchiver, Total Commander support TAR.

Programming Language Support

Standards and Extensions

Over its history TAR has accumulated several standards:

• V7 TAR - the original Unix Version 7 format (1979)
• POSIX 1003.1-1988 (USTAR) - standardized format with extended attributes
• GNU TAR - GNU extensions for long names and sparse files
• POSIX 1003.1-2001 (PAX) - modern standard with Unicode, ACL, xattr support

Most modern utilities work with any of the variants automatically, providing maximum compatibility.

Limitations and Alternatives

When Converting to TAR is Not Optimal

• Transfer to Windows environments - a recipient without 7-Zip or WinRAR cannot open TAR with built in tools on Windows older than version 10.
• Storage on limited disks - the TAR archive size equals the sum of all file sizes, which can be problematic for large collections.
• Network transfer with traffic caps - uncompressed TAR requires more bandwidth.

Alternative Scenarios

If both archiving and compression are needed:

• ZIP to TAR.GZ - the standard compressed Unix format with fast extraction
• ZIP to TAR.BZ2 - better text compression than GZIP
• ZIP to TAR.XZ - maximum compression in Unix style

Pure TAR is optimal as an intermediate format when separate processing is needed or when compression is not required. In most scenarios compressed TAR family variants are used.