.tgz File Extension

What kind of file is a .tgz?

A .tgz file is normally a TAR archive compressed with Gzip. It is a compact spelling of .tar.gz. TAR first bundles files, directories, and metadata into one stream; Gzip then compresses that stream losslessly.¹

The appropriate media type for the outer stream is usually application/gzip, although its IETF registration lists .gz, not .tgz, as the file extension.² A genuine Gzip member begins with magic bytes 1F 8B; the common third byte 08 identifies DEFLATE compression. After decompression, a normal .tgz payload should contain a valid TAR archive.³

How do I open a .tgz on my computer?

• On Windows, use the built-in tar command or an archive app such as 7-Zip.
• On macOS, double-click the file to try Archive Utility, or use tar in Terminal.
• On Linux and Unix, use GNU tar or a desktop archive manager.

GNU tar recognizes .tgz as Gzip-compressed TAR and can inspect or extract it directly.¹ List an unfamiliar archive before unpacking it:

tar -tzf package.tgz

Then extract it into a new, empty directory. Review member paths for absolute names, .. parent references, symbolic links, device nodes, and unexpected executables. GNU tar recommends isolating untrusted archives because unsafe paths and links can overwrite files outside the intended location.⁴

Poly support for .tgz

Poly stores, syncs, shares, versions, downloads, and finds .tgz files by name. Poly does not currently infer Gzip from the .tgz suffix, decompress either layer, preview the archive, index member names or contents, or give the Poly agent access to files inside it.

Download the archive and extract it with a trusted local utility when you need its contents. Add the extracted files to Poly separately to receive the preview, search, metadata, and agent features available for their formats.

History of .tgz

Jean-loup Gailly wrote the original GNU gzip program, with decompression code by Mark Adler. The project dates to 1992 and was developed as a free replacement for the older Unix compress utility.⁵ RFC 1952 documented the Gzip file format in 1996, and RFC 6713 registered application/gzip in 2012.²³

The .tgz convention combines the roles of TAR and Gzip in a short suffix. GNU gzip recognizes it as shorthand for .tar.gz and can use .tgz when compressing a filename ending in .tar would otherwise require truncation. GNU tar also maps .tgz to Gzip for automatic compression selection.¹⁶

Working with .tgz and alternatives

Gzip includes a CRC-32 for accidental-corruption checks, but it does not authenticate the archive. A small compressed file can also expand substantially. Apply storage and time limits, inspect TAR members before extraction, and verify a trusted digest or signature when provenance matters.²³

Converting to ZIP or another tarball requires decompressing or extracting and then creating a new archive. Changing only the suffix changes no bytes.