How To: Open a Gz file

You have just downloaded a .gz file, or a .tar.gz file. Perhaps you have a web site backup or you have downloaded web server access logs, and the file is in tar, gz or tar.gz format. What is a .gz file or a .tar.gz file, and how do you open them under Windows?

What is a .gz file? What is a .tar.gz file?

A .gz file is a compressed file. The extension .gz stands for GNU Zip. You have probably heard of the GNU Project, or GNU Linux, and you may also know how to open a Zip file. GNU Zip or .gz is a free GNU software implementation of a compression algorithm. It's similar to Zip, but free, not proprietary. It does the same sort of job, but the compression algorithms used by GNU Zip .gz are different from those used in Zip files and so you need different software to open .gz files.

A .tar file is a Unix tape archive. That's what the extension tar comes from. It's a specification that was written long ago for archiving multiple files on magnetic tape. It includes headers that give information about the files in the archive, as well as the files themselves. Although designed in the days when computers stored data on magnetic tape, the format and structure can be used to create archives in any type of file.

A .tar.gz file is a tape archive .tar file that has been GNU Zipped. In the Unix and Linux world, the task is performed by two separate utilities. You would first run the tar utility to create a single archive .tar file, and then compress it using GNU Zip, which adds the .gz extension. This is different from Zip tools and other compression utilities commonly used under Windows, where the archiving and the compression are done at the same time by a single process.

When data is archived and compressed on a Unix or Linux system, it is usually in the .tar.gz format. Windows has no built-in support for tar archives or gz compressed files. In order to open a tar.gz file you will need to use another application.

Open .gz files in Microsoft Windows

ssIf you use Microsoft Windows then recommends BitZipper. BitZipper is an archive manager that lets you open .tar files, .gz files and just about every other popular compressed and encoded file format. It can create archives using most of these formats too, and it's also a fast and powerful backup tool.

BitZipper has a Wizard interface that makes it easy to use even if you have no experience of working with compressed files. For more experienced users there is a Classic interface, shown on the right.

We have tested several Windows archive managers that support the .tar and .gz formats. BitZipper is one of the few that can manage to open large website backup files. It can open archives several hundred megabytes or more in size and allow you to extract individual files without throwing up error messages, crashing or bringing the computer to a halt.

BitZipper runs on Windows 2000, XP and Vista.

Open .gz files in Apple Mac OS X

Stuffit lets you open Rar files on a MacIf you use an Apple Mac computer then you can use Stuffit to open .gz files. Stuffit is one of the most long established Mac utilities. It gives you a complete set of tools for opening and creating the many and various types of compressed archive that you may come across on the Internet.

Stuffit can open .gz files and also Rar files, Zip files, Tar files and many more. It's "Quick Look" feature saves you time by letting you peek inside archives without opening them.

You can also use Stuffit to create archives in the most popular formats. This allows you to save space on your hard drive and make smaller files to send to your friends by compressing MP3s, PDFs, photos and other files with no loss of quality.

Stuffit requires Mac OS X 10.4 or higher.