The zstd CLI provides extensive compression options, from ultra-fast modes to maximum compression settings.
Basic Compression
Compression Levels
# Default compression (level 3)
zstd file.txt
# Specific level (1-19)
zstd -1 file.txt # Fastest
zstd -9 file.txt # Balanced
zstd -19 file.txt # Best compression
Higher compression levels generally produce better compression ratios but are slower and use more memory. Compression speed roughly halves every 2 levels.
Ultra Compression
# Unlock levels 20-22 (requires more memory)
zstd --ultra -20 file.txt
zstd --ultra -22 file.txt # Maximum compression
# Maximum compression preset
zstd --max file.txt
Ultra compression levels (20-22) require significantly more memory for both compression and decompression. Level 22 with --max is very slow and resource-intensive.
Fast Compression
# Ultra-fast compression modes
zstd --fast file.txt # --fast=1 (default)
zstd --fast=2 file.txt
zstd --fast=5 file.txt # Faster, lower ratio
--fast setting provides very fast compression at the cost of compression ratio. Higher values increase speed but reduce compression.
Multi-threading
Thread Options
# Use specific number of threads
zstd -T4 file.txt
# Use all available CPU cores
zstd -T0 file.txt
# Single-threaded mode (lower memory usage)
zstd --single-thread file.txt
-T1 spawns 1 compression thread in parallel with I/O, while --single-thread serializes I/O and compression for lower memory usage.
Auto-threading
# Use physical cores (default)
zstd -T0 --auto-threads=physical file.txt
# Use logical cores
zstd -T0 --auto-threads=logical file.txt
Advanced Compression Options
Long Distance Matching
# Enable long distance matching (128 MiB window)
zstd --long file.tar
# Specify window log size
zstd --long=27 file.tar # Default
zstd --long=30 file.tar # Larger window
| Method | Ratio | Compression Speed | Decompression Speed |
|---|
zstd -1 | 5.065 | 284.8 MB/s | 759.3 MB/s |
zstd -1 --long | 17.426 | 220.6 MB/s | 1638.4 MB/s |
zstd -10 | 6.504 | 29.5 MB/s | 771.3 MB/s |
zstd -10 --long | 21.949 | 75.6 MB/s | 1632.6 MB/s |
Adaptive Compression
# Dynamically adapt compression level to I/O
zstd --adapt file.txt
# Constrain adaptation range
zstd --adapt=min=1,max=10 file.txt
Adaptive compression is not reproducible due to dynamic level changes. It works with multi-threading and --long mode but not with --single-thread.
Job Size
# Set compression job size (for multi-threading)
zstd -T0 -B 1MiB file.txt
zstd -T0 -B 0 file.txt # Automatic (default)
Rsyncable Compression
# Create rsync-friendly compressed files
zstd --rsyncable file.txt
zstd --rsyncable -B 1MiB file.txt
Do not use --rsyncable with --single-thread. It may reduce effectiveness with long distance matching.
Integrity Checks
# Add XXH64 checksum (default)
zstd file.txt
# Disable checksum
zstd --no-check file.txt
Content Size
# Store original size in header (default)
zstd file.txt
# Disable content size
zstd --no-content-size file.txt
Output Control
Output Files
# Specify output file
zstd file.txt -o compressed.zst
# Write to stdout
zstd -c file.txt > output.zst
# Keep input files (default)
zstd -k file.txt
# Remove input files after compression
zstd --rm file.txt
Force Overwrite
# Overwrite existing files
zstd -f file.txt
# Force stdout even to terminal
zstd -fc file.txt
Streaming Compression
Stream Size
# Specify exact input size for streaming
cat file.txt | zstd --stream-size=12345 > file.zst
The stream size must be exact. Incorrect values cause errors. This helps optimize compression parameters.
Size Hint
# Provide approximate size hint for optimization
cat file.txt | zstd --size-hint=10KiB > file.zst
Target Block Size
# Create blocks of approximately specified size
zstd --target-compressed-block-size=64KiB file.txt
# Zstandard format (default)
zstd --format=zstd file.txt
# gzip format (requires zlib support)
zstd --format=gzip file.txt
# xz format (requires lzma support)
zstd --format=xz file.txt
# lzma format (requires lzma support)
zstd --format=lzma file.txt
# lz4 format (requires lz4 support)
zstd --format=lz4 file.txt
Literals Compression
# Force compressed literals
zstd --compress-literals file.txt
# Force uncompressed literals
zstd --no-compress-literals file.txt
Match Finder
# Enable row-based match finder (greedy/lazy/lazy2 strategies)
zstd --row-match-finder file.txt
# Disable row-based match finder
zstd --no-row-match-finder file.txt
File Filtering
# Only compress uncompressed files
zstd --exclude-compressed *.txt *.log *.data
.jpg, .mp3, .zst).
Advanced Parameter Control
Custom Parameters
# Set advanced compression parameters
zstd --zstd=wlog=23,clog=23,hlog=22,slog=6,mml=3,tlen=48,strat=6 file.txt
# Override specific parameters
zstd -19 --zstd=strategy=9 file.txt
Show Default Parameters
# Display parameters for compression level
zstd --show-default-cparams -19 file.txt