🗜️ Linux/Unix: Compression Tools – tar, gzip, zip, bzip2, xz, 7z Explained with Examples

🧲 Introduction – Why Learn Compression in Linux?

Compression tools are essential in Linux for reducing file sizes, archiving data, sharing via networks, and backups. Linux offers powerful utilities like tar, gzip, zip, bzip2, xz, and 7z—each with different compression algorithms, speeds, and use cases.

🎯 In this guide, you’ll learn:

• How to compress and extract files using popular Linux tools
• Key differences between formats like .tar.gz, .zip, .bz2, .xz, and .7z
• Practical commands with output and explanations

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📦 1. tar – Archive Multiple Files Together

✅ What is tar?

tar (tape archive) combines multiple files into a single archive. It doesn’t compress by default, but it’s often used with gzip, bzip2, or xz.

🛠️ Syntax:

tar [options] archive.tar file...

🔹 Common Options:

Option	Description
-c	Create archive
-x	Extract archive
-v	Verbose (list files)
-f	Specify filename
-z	Use gzip
-j	Use bzip2
-J	Use xz

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🧪 Example 1: Create a .tar.gz archive

tar -czvf archive.tar.gz folder/

📤 Output:

folder/
folder/file1.txt
folder/file2.log

🧪 Example 2: Extract a .tar.gz archive

tar -xzvf archive.tar.gz

🧠 Extensions:

• .tar – uncompressed archive
• .tar.gz or .tgz – gzip-compressed
• .tar.bz2 – bzip2-compressed
• .tar.xz – xz-compressed

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📑 2. gzip – Compress Single Files Fast

✅ What is gzip?

gzip compresses a single file, replacing the original with .gz. It’s fast and commonly used with tar.

🛠️ Syntax:

gzip [options] file
gunzip file.gz  # to decompress

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🧪 Example:

gzip logfile.log

📤 Output:

logfile.log.gz

To decompress:

gunzip logfile.log.gz

🧠 gzip is fast, but not as compact as bzip2 or xz.

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📁 3. zip – Compress with Windows Compatibility

✅ What is zip?

zip compresses and archives in one step. It works well for cross-platform use (Linux ↔ Windows).

🛠️ Syntax:

zip archive.zip file1 file2
unzip archive.zip

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🧪 Example:

zip myfiles.zip file1.txt file2.txt

📤 Output:

  adding: file1.txt (deflated 60%)
  adding: file2.txt (deflated 40%)

🧠 Supports individual file compression, unlike tar.

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🧬 4. bzip2 – Higher Compression Ratio than gzip

✅ What is bzip2?

bzip2 compresses single files with better compression than gzip, but it’s slower.

🛠️ Syntax:

bzip2 file
bunzip2 file.bz2

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🧪 Example:

bzip2 backup.sql

📤 Output:

backup.sql.bz2

To decompress:

bunzip2 backup.sql.bz2

🧠 Use tar -j to create .tar.bz2 archives.

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⚛️ 5. xz – Best Compression Ratio (Slow)

✅ What is xz?

xz compresses single files with high compression ratio, better than gzip/bzip2, but takes more time.

🛠️ Syntax:

xz file
unxz file.xz

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🧪 Example:

xz large.log

📤 Output:

large.log.xz

To decompress:

unxz large.log.xz

🧠 Use tar -J to create .tar.xz archives.

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🔐 6. 7z – High-Ratio Compression with AES Encryption

✅ What is 7z?

7z uses the LZMA algorithm, supports strong encryption, and offers high compression ratios. Great for backups and large archives.

📦 Install:

sudo apt install p7zip-full

🛠️ Syntax:

7z a archive.7z file1 file2
7z x archive.7z

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🧪 Example 1: Create a 7z archive

7z a secure.7z secrets.txt

🧪 Example 2: Extract a 7z archive

7z x secure.7z

🧠 Add -p for password:

7z a -pMySecret secure.7z secrets.txt

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🧠 Comparison Table of Compression Tools

Tool	Compresses	Archive Support	Speed	Ratio	Encryption	Ideal Use Case
tar	❌ (archive only)	✅ (with gzip, etc)	Fast	–	❌	Combining files
gzip	✅	❌	Fast	Moderate	❌	Logs, single file compression
zip	✅	✅	Medium	Moderate	✅ (basic)	Cross-platform sharing
bzip2	✅	❌	Slow	High	❌	Backups, smaller files
xz	✅	❌	Very Slow	Very High	❌	Archiving large files
7z	✅	✅	Medium	Highest	✅ (AES)	Encrypted backups

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📌 Summary – Recap & Next Steps

Linux offers a tool for every compression need—from fast logs to encrypted archives. Whether you’re scripting backups, archiving files, or sending compressed content, these tools offer flexibility, speed, and control.

🔍 Key Takeaways:

• Use tar + gzip for common archives.
• Use zip for cross-platform compatibility.
• Use xz or 7z for best compression ratio.
• Use bzip2 for balance between speed and space.

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❓ FAQs

❓ How do I compress a directory into .tar.gz?
✅ Use:

tar -czvf archive.tar.gz dirname/

❓ Which format offers best compression?
✅ xz and 7z offer the best ratios but take more time.

❓ Can I extract .tar.gz files with unzip?
❌ No. Use:

tar -xzvf archive.tar.gz

❓ Can I password-protect with zip or 7z?
✅ Yes. Use:

zip -e secure.zip file.txt
7z a -p password archive.7z

❓ How to list contents of a tar archive without extracting?
✅ Use:

tar -tvf archive.tar.gz

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