gzip (GNU Zip Compressed)
GZ is the file extension for gzip-compressed files, the standard compression tool on Unix and Linux systems. Gzip compresses a single file using the DEFLATE algorithm — to compress multiple files, it is typically paired with TAR to create .tar.gz (tgz) archives.
MIME Type
application/gzip
Type
Binary
Compression
Lossless
Advantages
- + Universal support on Unix/Linux and in HTTP content encoding
- + Fast decompression speed
- + Simple single-file compression with integrity checking
Disadvantages
- − Compresses only one file — needs TAR for directories
- − Lower compression ratio than bzip2, xz, or Zstandard
- − No encryption support built into the format
When to Use .GZ
Use gzip for compressing single files, web server content encoding, and pairing with TAR for multi-file archives.
Technical Details
Gzip uses DEFLATE compression (LZ77 + Huffman coding) with a 10-byte header containing a magic number, timestamp, and OS identifier. A CRC-32 checksum and original file size are appended as a trailer.
History
Jean-loup Gailly and Mark Adler created gzip in 1992 as a free replacement for the Unix compress utility, which was encumbered by LZW patents. Gzip became the default compression for HTTP content encoding and Linux packages.