system:linux:file-compression-archiving

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system:linux:file-compression-archiving [2026/01/26 20:41] – removed - external edit (Unknown date) 127.0.0.1system:linux:file-compression-archiving [2026/02/01 21:08] (current) – external edit 127.0.0.1
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 +====== Linux : Compression and Archiving ======
  
 +===== What is Compression? =====
 +
 +**Compression** is a process or technique to reduce the size of a data file. This is achieved using specific algorithms that identify patterns in the data to reduce its size.
 +
 +Compression is divided into two types:
 +
 +  * **Lossless Compression**: Data is compressed without any loss of information. The decompressed data is identical to the original.
 +  * **Lossy Compression**: Some information is intentionally removed to reduce file size. The decompressed result may not be identical to the original.
 +
 +===== What is Archiving? =====
 +
 +Before exploring compression, it is important to understand **archiving**.
 +
 +**Archiving** is the process of collecting multiple files or directories into a single file. This archive can then be compressed using compression tools.
 +
 +==== tar ====
 +
 +**tar** is a common archiving tool on Linux. Example usage:
 +
 +<code bash>
 +tar -cvf archive.tar file1 file2 directory
 +</code>
 +
 +In the example above:
 +  * <code>-c</code>: Create a new archive
 +  * <code>-v</code>: Verbose mode (shows detailed process)
 +  * <code>-f</code>: Specifies the archive file name
 +
 +<WRAP info>
 +You can add compression options: <code>-z</code> for gzip, <code>-j</code> for bzip2, or <code>-J</code> for xz.
 +</WRAP>
 +
 +===== Compression Tools =====
 +
 +Common compression tools on Linux:
 +
 +^ Compression Tool ^ Compression Algorithm ^
 +| **gzip**  | DEFLATE |
 +| **bzip2** | Burrows-Wheeler |
 +| **xz**    | LZMA |
 +| **zip**   | DEFLATE |
 +
 +==== gzip ====
 +
 +**gzip** is a widely used compression utility using the **DEFLATE** algorithm.
 +
 +  * Compress a file:
 +    <code bash>
 +    gzip filename
 +    </code>
 +    → Produces <code>filename.gz</code>
 +
 +  * Decompress a file:
 +    <code bash>
 +    gunzip filename.gz
 +    # or
 +    gzip -d filename.gz
 +    </code>
 +
 +  * View compression info:
 +    <code bash>
 +    gzip -l filename.gz
 +    </code>
 +
 +==== bzip2 ====
 +
 +**bzip2** uses the **Burrows-Wheeler** algorithm for better compression than gzip.
 +
 +  * Compress a file:
 +    <code bash>
 +    bzip2 filename
 +    </code>
 +    → Produces <code>filename.bz2</code>
 +
 +  * Decompress a file:
 +    <code bash>
 +    bunzip2 filename.bz2
 +    # or
 +    bzip2 -d filename.bz2
 +    </code>
 +
 +  * View compression info:
 +    <code bash>
 +    bzcat filename.bz2 | wc -c
 +    </code>
 +
 +==== xz ====
 +
 +**xz** uses the **LZMA (Lempel-Ziv-Markov chain algorithm)**. It offers higher compression ratios but is slower and more resource-intensive.
 +
 +  * Compress a file:
 +    <code bash>
 +    xz filename
 +    </code>
 +    → Produces <code>filename.xz</code>
 +
 +  * Decompress a file:
 +    <code bash>
 +    unxz filename.xz
 +    # or
 +    xz -d filename.xz
 +    </code>
 +
 +  * View compression info:
 +    <code bash>
 +    xz -l filename.xz
 +    </code>
 +
 +==== zip ====
 +
 +**zip** is commonly used to compress and archive multiple files.
 +
 +  * Compress files:
 +    <code bash>
 +    zip archive.zip file1 file2 folder1
 +    </code>
 +
 +  * Recursively compress a folder:
 +    <code bash>
 +    zip -r archive.zip folder1
 +    </code>
 +
 +  * Add files to existing zip:
 +    <code bash>
 +    zip -u archive.zip file3
 +    </code>
 +
 +  * Password-protect a zip:
 +    <code bash>
 +    zip -r -e archive.zip folder1
 +    </code>
 +
 +  → Produces <code>archive.zip</code>
 +
 +  * Decompress:
 +    <code bash>
 +    unzip archive.zip
 +    </code>
 +
 +  * View compression info:
 +    <code bash>
 +    unzip -l archive.zip
 +    </code>
 +
 +===== Archiving and Compression with tar =====
 +
 +**tar** supports built-in compression in one command:
 +
 +==== tar + gzip ====
 +<code bash>
 +# Compress
 +tar -czvf archive.tar.gz directory/
 +# Decompress
 +tar -xzvf archive.tar.gz
 +</code>
 +
 +==== tar + bzip2 ====
 +<code bash>
 +# Compress
 +tar -cjvf archive.tar.bz2 directory/
 +# Decompress
 +tar -xjvf archive.tar.bz2
 +</code>
 +
 +==== tar + xz ====
 +<code bash>
 +# Compress
 +tar -cJvf archive.tar.xz directory/
 +# Decompress
 +tar -xJvf archive.tar.xz
 +</code>
 +
 +<WRAP info>
 +Explanation of flags:
 +
 +  * <code>-c</code>: Create archive  
 +  * <code>-x</code>: Extract archive  
 +  * <code>-z</code>: Use gzip  
 +  * <code>-j</code>: Use bzip2  
 +  * <code>-J</code>: Use xz  
 +  * <code>-v</code>: Verbose (detailed output)  
 +  * <code>-f</code>: Specify archive file name
 +</WRAP>