Ubuntu tar Basics: Compression, Extraction & Avoiding Common Mistakes

tar Basics - Compression, Extraction & Accident Prevention
Reading time: ~8 min Level: Intermediate

What You'll Learn

  • How to compress, extract, and list contents with tar
  • Understand the differences between .tar.gz / .tgz / .tar
  • How to avoid common accidents (extracting to wrong locations, overwriting, path issues)

💡 Quick Summary

Start with these commands - they'll cover most cases:

  • Create (gzip): tar -czf archive.tar.gz DIR/
  • Extract: tar -xzf archive.tar.gz
  • List contents: tar -tzf archive.tar.gz
  • Specify destination: tar -xzf archive.tar.gz -C /path/to/dir

Table of Contents

  1. tar File Formats Overview
  2. Creating Archives (Compression)
  3. Extracting Archives
  4. Listing Contents
  5. Common Accidents & Prevention
  6. Other Formats (.tar / .tar.bz2 / .tar.xz)

⚠️ Prerequisites

  • OS: Ubuntu
  • Shell: bash
  • Permissions: Regular user (use sudo when needed)

1. tar File Formats Overview

  • .tar: Files bundled together (no compression)
  • .tar.gz / .tgz: Bundled with tar, compressed with gzip
  • .tar.bz2: Bundled with tar, compressed with bzip2
  • .tar.xz: Bundled with tar, compressed with xz

💡 Most commonly seen: .tar.gz / .tgz. Start with these.

2. Creating Archives (Compression)

2-1. Create .tar.gz from Directory (Basic)

$ tar -czf archive.tar.gz DIR/
  • c: create
  • z: gzip compression
  • f: specify filename (required - without it, unexpected behavior may occur)

2-2. Bundle Multiple Files/Directories

$ tar -czf archive.tar.gz DIR1/ DIR2/ file.txt

3. Extracting Archives

3-1. Extract to Current Directory (Basic)

$ tar -xzf archive.tar.gz
  • x: extract
  • z: gzip
  • f: specify file

3-2. Specify Destination Directory (Recommended for Safety)

$ tar -xzf archive.tar.gz -C /path/to/dir

💡 Until you're comfortable, always use -C to avoid extraction accidents.

4. Listing Contents (Always Check Before Extracting)

4-1. List All Contents (.tar.gz)

$ tar -tzf archive.tar.gz

4-2. View Just the Beginning (for Long Lists)

$ tar -tzf archive.tar.gz | head

5. Common Accidents & Prevention (Most Important)

❌ Accident A: Extracting to Wrong Location

Causes:

  • Not knowing your current directory
  • Not using -C flag

Prevention:

  1. Check current directory before extracting: pwd
  2. Always specify destination with -C
$ pwd
$ tar -xzf archive.tar.gz -C /tmp

❌ Accident B: Archive Contains Absolute Paths (e.g., starts with /)

Danger:

  • Archive paths like /etc/... are absolute paths
  • Extraction could overwrite system files

Prevention:

  • Check paths with tar -tzf before extracting
  • When uncertain, extract to safe location like /tmp first
$ mkdir -p /tmp/tar-test
$ tar -xzf archive.tar.gz -C /tmp/tar-test

❌ Accident C: Overwriting Existing Files

Prevention:

  • Don't extract directly to production directories
  • First extract to empty working directory and verify contents
$ mkdir -p ~/work/extract-test
$ tar -xzf archive.tar.gz -C ~/work/extract-test

⚠️ Accident D: Files Scattered Instead of Single Directory

Depending on how the archive was created, files may not be in a single directory.

Best Practice (when creating):

  • Navigate to the parent of the directory you want to archive
  • Example: To create DIR/ as a single directory
$ cd /path/to
$ tar -czf DIR.tar.gz DIR/

6. Other Formats (.tar / .tar.bz2 / .tar.xz)

Use these when needed:

6-1. .tar (No Compression)

Create:

$ tar -cf archive.tar DIR/

Extract:

$ tar -xf archive.tar

6-2. .tar.bz2

Extract:

$ tar -xjf archive.tar.bz2

6-3. .tar.xz

Extract:

$ tar -xJf archive.tar.xz

Verification

After extraction, verify files are in the expected location:

$ ls -la

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📋 Test Environment

Commands tested on Ubuntu 24.04 LTS / bash 5.2.

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