How to Use the Command 'lz4' (with Examples)

LZ4 is a fast and efficient lossless compression algorithm that provides users the ability to compress and decompress files with ease. The LZ4 command-line tool is particularly useful for quickly compressing and decompressing data, especially when dealing with large datasets. Its speed and straightforward syntax make it an ideal choice for users who need to expedite their data compression workloads without compromising on performance.

Use Case 1: Compress a File

Code:

lz4 path/to/file

Motivation:

Compressing files can significantly reduce file sizes, making them easier to store and transfer. The LZ4 tool performs this task quickly, with minimum impact on system resources. It’s particularly beneficial for users needing to manage disk space efficiently or quickly share files over networks.

Explanation:

• lz4: Invokes the LZ4 tool.
• path/to/file: Specifies the file to be compressed. The file is compressed into a new file with the same name but with an additional .lz4 extension.

Example Output:

Compressed filename: file.lz4
Compression ratio: 1.8
Time taken: 0.03 seconds

Use Case 2: Decompress a File

Code:

lz4 -d file.lz4

Motivation:

Decompressing files is a critical operation for accessing or restoring data to its original state. This command is essential for retrieving the contents of compressed files for further use or analysis.

Explanation:

• lz4: Invokes the LZ4 tool.
• -d: The ’d’ flag stands for ‘decompress’, instructing LZ4 to expand the file back to its original form.
• file.lz4: Specifies the compressed input file that needs to be decompressed.

Example Output:

Decompressed filename: file
Decompression complete
Time taken: 0.02 seconds

Use Case 3: Decompress a File and Write to stdout

Code:

lz4 -dc file.lz4

Motivation:

Outputting decompressed data directly to standard output (‘stdout’) is useful for immediate processing or piping the data into another command without needing to write it to a file. This technique is common in data processing pipelines.

Explanation:

• lz4: Invokes the LZ4 tool.
• -d: Specifies decompression.
• -c: Indicates output should be directed to the console (stdout).

Example Output:

{output of decompressed data displayed directly on the terminal screen}

Use Case 4: Package and Compress a Directory and Its Contents

Code:

tar cvf - path/to/directory | lz4 - dir.tar.lz4

Motivation:

Packaging a directory and its contents into a single compressed file simplifies archiving and transfer while saving storage space. This is particularly useful for backing up directories or when transferring them across networks.

Explanation:

• tar cvf -: Uses the tar command to create an archive of the specified directory or file stream, indicated by -.
• path/to/directory: The directory to be archived.
• |: Pipes the output of the previous command as input to the next.
• lz4 -: Invokes LZ4 to compress the incoming data stream.
• dir.tar.lz4: The output file in which the compressed directory archive is saved.

Example Output:

Packing path/to/directory
Compressed and saved as dir.tar.lz4
Time taken: 0.4 seconds

Use Case 5: Decompress and Unpack a Directory and Its Contents

Code:

lz4 -dc dir.tar.lz4 | tar -xv

Motivation:

Decompressing and unpacking a directory at once is streamlined through this command, useful when you need to access stored files within a compressed directory. This can facilitate rapid deployment of archived applications or data sets.

Explanation:

• lz4 -dc: Invokes LZ4 to decompress the .lz4 file to stdout.
• dir.tar.lz4: The input compressed file.
• |: Pipes the decompressed data directly into the next command.
• tar -xv: Extracts the tar archive, where -x denotes extract and -v means verbose, listing the files as they are extracted.

Example Output:

Extracting directory/
Extracting directory/file1
...
Extraction complete
Time taken: 0.5 seconds

Use Case 6: Compress a File Using the Best Compression

Code:

lz4 -9 path/to/file

Motivation:

Achieving higher compression ratios is crucial when minimizing space usage is a priority, such as in storage-constrained environments or when attempting to reduce transfer times over bandwidth-limited networks.

Explanation:

• lz4: Invokes the LZ4 tool.
• -9: Requests maximum compression, striving for the best possible ratio at the expense of taking more time compared to default settings.
• path/to/file: The file targeted for compression.

Example Output:

Compressed filename: file.lz4
Enhanced compression ratio: 2.5
Time taken: 0.07 seconds

Conclusion:

LZ4 offers a broad range of capabilities for both compressing and decompressing data efficiently. Whether you’re preparing files for archiving, optimizing storage space, or constructing data pipelines, LZ4 provides the flexibility and speed needed to handle modern data processing challenges seamlessly.