Explaining .tar.gz file format

The aim of this page📝 is to explain file compression and archiving based on the particular example of combining tar and gzip in software distribution.

• A tar file (short for Tape Archive) bundles multiple files into a single archive.
• Initially designed for sequential I/O devices (like magnetic tapes) lacking their own file systems.
• Retains metadata (permissions, ownership, timestamps).

Why Does Tar Exist?

• Historical context: Early tape drives and raw disks had variable-length data blocks, leading to wasted space.
• Sequential I/O devices: Tar suited devices where files were written sequentially.
• Collecting files: Ideal for bundling related files together.

Advantages of Tar:

• Simplicity: Easy to use.
• Cross-Platform: Works across Unix-like systems.
• No Compression: Focuses on bundling files.
• Software Distribution: Commonly used for distributing software.

Combining Tar and Gzip:

• Why?: To get both bundling and compression.
• Result: The .tar.gz file contains a tar archive compressed with gzip.

Usage:

• Creating: tar -czvf archive.tar.gz file1 file2 ...
• Extracting: tar -xzvf archive.tar.gz

ZIP vs. Tar/Gzip:

ZIP:

• Retains metadata.
• Efficient for individual files.
• Widely supported but not ideal for software distribution.

.tar.gz:

• Preserves metadata.
• Efficient storage and distribution.
• Popular in Unix environments.

LINKS

• Tar (Wikipedia)
• Gzip (GNU Zip)
• ZIP (Wikipedia)

ANKI

Question 1

What does a tar file do?

Answer 1

A tar file bundles multiple files into a single archive, preserving metadata.

Question 2

Why was tar initially designed?

Answer 2

To write data to sequential I/O devices (like magnetic tapes) lacking their own file systems.

Question 3

What does .tar.gz combine?

Answer 3

A tar archive (bundling) with gzip compression.

Question 4

Why is ZIP not ideal for software distribution?

Answer 4

ZIP lacks seamless metadata preservation (Linux permissions) and efficient compression for large software packages.

Question 5

What’s the benefit of .tar.gz in Unix environments?

Answer 5

It combines bundling, metadata preservation, and efficient compression.