Configuration Reference

Detailed configuration options for checkle.

Performance Parameters

chunk-size-kb

Controls the size of data chunks read from files.

• Type: Integer
• Default: 1024 (1MB)
• Range: 4 - 65536
• Unit: Kilobytes

Impact:

• Larger chunks: Better sequential throughput, more memory
• Smaller chunks: Less memory, better for slow storage

Recommendations:

parallel-readers

Number of threads for parallel file reading.

• Type: Integer
• Default: Auto (based on CPU cores)
• Range: 1 - 64
• Auto logic: min(CPU_cores, 8)

Impact:

• More threads: Better parallelization for large files
• Fewer threads: Less memory usage, less I/O contention

Guidelines:

• Files <64MB: Always single-threaded
• Files ≥64MB: Multi-threaded based on size
• I/O bound after ~16 threads

max-files-batch

Maximum files to process simultaneously.

• Type: Integer
• Default: 1000
• Range: 1 - 10000

Impact:

• Larger batch: Better throughput for many small files
• Smaller batch: Less memory usage

parallel-files

Files to verify in parallel (verify-many only).

• Type: Integer
• Default: 4
• Range: 1 - 32

Impact:

• More parallel: Faster verification of many files
• Less parallel: Lower system load

Algorithm Configuration

algo

Hash algorithm selection.

• Type: Enum
• Values: md5, sha256
• Default: md5

Characteristics:

Output Configuration

format

Output format for checksums.

• Type: Enum
• Values: text, json, csv
• Default: text (auto-detected from file extension)

Auto-detection:

• .json → JSON format
• .csv → CSV format
• Others → text format

pretty

Display results in formatted table.

• Type: Boolean
• Default: false
• Output: stderr (doesn't interfere with stdout)

per-file

Create individual checksum files.

• Type: Boolean
• Default: false
• Naming: <filename>.<algo> (e.g., file.txt.md5)

absolute-paths

Use absolute paths in output.

• Type: Boolean
• Default: false (relative paths)

Filtering Configuration

include

Patterns for files to include.

• Type: String (multiple allowed)
• Syntax: Glob patterns
• Default: Include all

Examples:

--include "*.txt"
--include "data/*.csv"
--include "**/*.fastq"

exclude

Patterns for files to exclude.

• Type: String (multiple allowed)
• Syntax: Glob patterns
• Default: Exclude none

Examples:

--exclude "*.tmp"
--exclude ".git/**"
--exclude "**/test/*"

no-ignore

Don't respect .gitignore rules.

• Type: Boolean
• Default: false (respect .gitignore)

recursive

Process directories recursively.

• Type: Boolean
• Default: false

Progress Configuration

no-progress

Disable progress bars.

• Type: Boolean
• Default: false (show progress)

Auto-disabled when:

• Output is not a terminal
• Quiet mode is enabled
• Single small file

Verification Configuration

fail-fast

Stop on first verification failure.

• Type: Boolean
• Default: false (verify all)
• Applies to: verify-many

failed-only

Show only failed verifications.

• Type: Boolean
• Default: false (show all)
• Applies to: verify-many

quiet

Suppress non-error output.

• Type: Boolean
• Default: false
• Applies to: verify-many

Resource Limits

Built-in limits for stability:

Default Behavior

Without options, checkle:

1. Uses MD5 algorithm
2. Auto-detects optimal thread count
3. Uses 1MB chunks
4. Shows progress bars
5. Outputs to stdout in text format
6. Processes single files/directories non-recursively
7. Respects .gitignore rules