How to Compress a Directory Full of Files Using tar and xz on the Terminal in Ubuntu

Introduction

This is an article about how to compress files and directories using tar and xz commands on the terminal in Ubuntu. In this article, you will find information about creating compressed archives from directories containing various types of files efficiently.

Understanding how to use these tools can be incredibly useful when managing backups or transferring large amounts of data over networks with limited bandwidth. The combination of tar for archiving and xz for compression provides a powerful method that maintains efficient storage space while preserving the integrity of your files.

Read this article to find out about compressing directories into tarballs using xz, how to extract them back to their original form when necessary, as well as tips on optimizing the process. We will also touch upon common pitfalls and provide solutions for them.

What is Tar?

tar stands for “tape archive,” which comes from its historical usage in archiving data onto magnetic tape drives. In today’s digital age, tar has become an essential command-line utility for bundling files into a single file (archive) while preserving directory structures and metadata such as permissions, timestamps, and ownership.

The basic syntax of the tar command is:

Commonly used options include:

• -c : Create a new archive.
• -x : Extract files from an existing archive.
• -t : List contents without modifying anything.

What is XZ?

XZ is a file compression format designed to achieve better compression ratios than gzip, bzip2 and other popular methods. It uses the LZMA (Lempel-Ziv-Markov chain algorithm) family of algorithms which provides excellent compression at the cost of higher CPU usage during compression compared to simpler algorithms like gzip.

To use XZ with tar, you specify --xz or -J.

Why Use Tar and XZ Together?

The combination of tar for archiving and XZ for compression offers several advantages:

• Preservation: The tar format ensures that directory structures are maintained in the archive.
• Efficiency: When compared to gzip, XZ typically provides better compression ratios. This makes it a great choice when storage space is limited but processing power is sufficient.
• Flexibility: Archives can be easily split into smaller parts or merged back together, allowing for convenient handling over networks and disk management.

Prerequisites

Before diving in, ensure that your system has the necessary tools installed:

Compressing a Directory with Tar and XZ on Ubuntu

Step 1: Create an Archive

Let’s begin by creating a compressed archive of a directory named my_folder. Navigate to where my_folder is located or specify its path using the full system address.

To create a compressed tarball:

• -c: tells tar to create a new archive.
• -J: specifies xz compression (equivalent to --xz).
• -f: filename argument, indicating the name of your output file.

Step 2: Verify the Archive

After creating the compressed archive, you might want to verify its contents:

The option -t lists files contained in an existing archive without modifying anything. The switch -v enables verbose output for better readability.

Step 3: Extracting Files

To extract the archived and compressed directory back to its original form:

• -x: instructs tar to extract files from an archive.
• my_archive.tar.xz: is the name of your created tarball file.

Advanced Usage

Compressing Without Preserving Permissions and Timestamps

Sometimes, you may not need the additional overhead of preserving permissions or timestamps. For a more lightweight compression:

The --owner, --group, and --numeric-owner options simplify ownership to root, reducing the archive’s size.

Splitting Archives into Smaller Parts

For large archives that may cause problems during transfer or storage:

The --multi-volume and --tape-length=3072M options split the archive into 3GB parts.

Incremental Backups

For incremental backups, use:

This creates an archive that only contains changes since the last backup recorded in /path/to/snarfile.

Troubleshooting Common Issues

Archive is Empty or Corrupted

If your tarball appears empty or shows signs of corruption:

• Ensure you used -c to create the archive.
• Verify there were no typos in file paths and options.

XZ Compression Takes Too Long

XZ compression can be slow due to its high efficiency. For faster operations, consider using other formats such as gzip (.tar.gz) or bzip2 (.tar.bz2).

Conclusion

This article has covered the basics of compressing directories into tarballs using XZ compression on Ubuntu through command line tools. From creation to extraction and even handling common issues, you now have a comprehensive understanding of how to manage your data efficiently.

For more advanced scenarios such as differential backups or customizing options further, explore tar’s extensive manual pages:

Happy archiving!