How to use the command `zlib-flate` (with examples)

zlib-flate is a raw zlib compression and decompression program that is part of the qpdf package. It allows you to compress and decompress files using zlib compression algorithm. This article will illustrate the various use cases of the zlib-flate command.

Use case 1: Compress a file

Code:

zlib-flate -compress < path/to/input_file > path/to/compressed.zlib

Motivation: You may want to compress a file to reduce its size and save disk space. Compressed files also consume less bandwidth when transferring data over a network.

Explanation:

• zlib-flate is the command used to compress or decompress files using zlib compression.
• -compress is the option used to specify the compression operation.
• < path/to/input_file is the input file path that needs to be compressed.
• > path/to/compressed.zlib is the output file path where the compressed file will be stored.

Example output: The command will compress the contents of the input file and store the compressed version in the specified output file. The size of the compressed file will be significantly smaller than the original input file.

Use case 2: Uncompress a file

Code:

zlib-flate -uncompress < path/to/compressed.zlib > path/to/output_file

Motivation: If you have a compressed file, you may want to uncompress it in order to retrieve the original contents. This can be useful when dealing with compressed data or files.

Explanation:

• zlib-flate is the command used to compress or decompress files using zlib compression.
• -uncompress is the option used to specify the decompression operation.
• < path/to/compressed.zlib is the input file path of the compressed file that needs to be uncompressed.
• > path/to/output_file is the output file path where the uncompressed contents will be stored.

Example output: The command will uncompress the contents of the compressed file and store the uncompressed version in the specified output file. The output file will contain the same contents as the original input file.

Use case 3: Compress a file with a specified compression level

Code:

zlib-flate -compress=compression_level < path/to/input_file > path/to/compressed.zlib

Motivation: The compression level determines the trade-off between file size and compression speed. Specifying a compression level allows you to control the balance between compression effectiveness and processing time.

Explanation:

• zlib-flate is the command used to compress or decompress files using zlib compression.
• -compress=compression_level is the option used to specify both the compression operation and the compression level.
• compression_level is a numeric value between 0 and 9, where 0 stands for the fastest compression (worst) and 9 stands for the slowest compression (best).
• < path/to/input_file is the input file path that needs to be compressed.
• > path/to/compressed.zlib is the output file path where the compressed file will be stored.

Example output: The command will compress the contents of the input file using the specified compression level and store the compressed version in the specified output file. The output file size and compression time will vary depending on the compression level chosen.

Conclusion:

The zlib-flate command provides a convenient way to compress and decompress files using the zlib compression algorithm. With various use cases, it allows you to control the compression level and retrieve the original contents of a compressed file. Whether it’s for optimizing storage, reducing network bandwidth, or handling compressed data, zlib-flate is a versatile tool.