GUI Tar Compressor can compress files into either .7z, .tar, .tbz, .tgz, .gz, .bz2, or .Z formats.
GUI Tar Extractor can uncompress files from .7z, .tar, .tar.gz, .dmg.gz, .svgz, .gz, .tgz, .tar.z, .z, .Z, .tar.Z, .taz, .tbz, .tbz2, .bz, .bz2, .rar, and .zip file formats.
List of supported files

GUI Tar 1.1 requires Mac OS 10.1 or later. GUI Tar has been tested on systems running Mac OS 10.1 through 10.4. There is no guarantee or support for Mac OS 10.0 or any future Mac OS incarnation at this time.

• Password-encrypted zip files are not supported under GUI Tar 1.1.
• Occasionally, a process cannot be canceled once is has begun running. This case has been observed when opening .dmg.gz files.
• GUI Tar does not ensure that both data and resource forks on Classic Mac OS files will be saved when compressed or archived.
• Making use of 7-zip (7z) archives requires Mac OS 10.3 or later.
• Mac OS 10.1 cannot compress or uncompress Bzipped tar archive (tbz) in a single step. Instead, GUI Tar needs to archive and then compress (and vice versa) in two separate steps.

To set GUI Tar as the default application to uncompress and unarchive files, follow these directions:

1. Select a supported file (.tar, .gz, .tgz, .bz2, et cetera) in a Finder window.
2. Open the Get Info window by one of these methods:
   · Select Get Info from the File menu
   · Press the Control key and click with the mouse and select Get Info from the context-sensitive menu
   · Right-click on the file and select Get Info from the context-sensitive menu
   · Use the key combination ⌘-I
3. Open the Open With section. Change the drop down menu to GUI Tar.
4. Click on the Change All button to set all of files of a particular type to open up using GUI Tar.
5. Close the Get Info window.

A wrapper is a program which acts as a graphical front end to a system utility.

Archiving is the process of collecting and storing a group of files and directories into one file. The tar utility performs this action.

Compression is the act of shrinking the size of a file, which is quite useful in sending large files over the internet.

Untar is used to uncompress and unarchive files from a variety of formats.

GUI Tar is a more comprehensive tool which not only encompasses all of Untar's functionality, but also adds the ability to archive and compress files.

Untar is a progressive application that will continue to develop in the foreseeable future. It is currently planned that Untar will be released with new features which will later be available in GUI Tar.

Tar is a UNIX utility which stands for Tape Archiver. Tar can either extract or combine files from/to a single .tar file. The UNIX manual (man) page for tar states:

The tar command creates, adds files to, or extracts files from an archive file in tar format. A tar archive is often stored on a magnetic tape, but can be a floppy or a regular disk file.

When a group of files are archived into a single file, they are not compressed. The gzip utility can take a file, such as somefile.tar, and compress it to make the file size smaller. Often, compressed and archived files will end with either the .tar.gz or .tgz extension, which signifies they have been archived and compressed.

Gunzip is the opposite of gzip, and it uncompresses a file, returning it to its original state.

• Tar archive: tar -xvf somefile.tar
• Gzipped tar archive: tar -xvzf somefile.tgz
• Bzipped tar archive: tar -xvjf somefile.tbz

• Tar archive: tar -cpvf somefile.tar file1 file2 file3
• Gzipped tar archive: tar -cpvzf somefile.tgz file1 file2 file3
• Bzipped tar archive: tar -cpvjf somefile.tbz file1 file2 file3