pigz

Additional Notes

pigz (Parallel Implementation of GZip) compresses and decompresses files using multiple CPU cores and threads. It produces standard gzip-compatible output that can be decompressed by regular gzip or gunzip.

For single-threaded compression, gzip uses one core. pigz splits the input into chunks, compresses each chunk in parallel using independent threads, and assembles the output into a standard gzip stream. Decompression is also faster with pigz on multi-core systems, though gzip decompression is less CPU-bound than compression.

Syntax

pigz [options] [files...]

Parameters

• files: One or more files to compress or decompress.

Common Options

• -p N, --processes N: Use N compression threads (default: number of online CPUs).
• -c, --stdout: Write to standard output, keep original files unchanged.
• -d, --decompress: Decompress (same as unpigz).
• -f, --force: Force overwrite of output files.
• -k, --keep: Keep the original input files after compression.
• -l, --list: List contents and properties of a compressed file.
• -r, --recursive: Process directories recursively.
• -t, --test: Test the integrity of a compressed file.
• -0 to -9: Compression level (0=fastest/no compression, 9=best compression, 6=default).
• -11: zlib-compatible compression level 11 (maximum compression).
• -z, --zlib: Produce zlib-compatible output instead of gzip.
• -K, --zlib-compress: Produce zlib-compressed data.
• -b, --blocksize KiB: Set the compression block size in KiB (default 128).
• -S suffix, --suffix suffix: Use a custom compression suffix (default .gz).
• -n, --no-name: Do not store original filename and timestamp.
• -T, --no-time: Do not store or restore timestamps.

Examples

pigz largefile.tar

Compress a tar file using all available CPU cores.

pigz -p 4 largefile.tar

Compress using exactly 4 threads.

pigz -d archive.gz

Decompress a gzip file (same as unpigz archive.gz).

pigz -k -9 important.txt

Compress at maximum compression, keeping the original file.

tar cf - mydir/ | pigz > mydir.tar.gz

Create a compressed tar archive using pigz in a pipeline.

pigz -l archive.gz

List details of a compressed file without decompressing.

unpigz archive.gz

Decompress using the unpigz alias.

pigz -t archive.gz

Test the integrity of a compressed file.

Practical Notes

• pigz produces standard .gz files. Decompress with gzip -d, gunzip, unpigz, or any gzip-compatible tool.
• Compression ratio is similar to gzip -9 regardless of thread count. More threads improve speed, not compression ratio.
• For maximum compression speed, use -p $(nproc) to use all available cores.
• For very large files, increase the block size with -b to improve compression ratio at the cost of memory usage.
• pigz uses about 32 KiB + 2 × block size × threads of memory. With default settings and 8 threads, expect ~2 MiB.
• Install with sudo apt install pigz or sudo yum install pigz.
• For decompression speed improvements, use unpigz which is the same binary with a different symlink name.
• For better compression ratios, consider xz or zstd instead of gzip/pigz.