Working with Files in Terminal

Updated May 9, 2026

File operations for copying, describing, validating, and analyzing local or remote files.

Available Commands

The fairspec file command provides utilities for working with files:

copy - Copy local or remote files
describe - Get file statistics and metadata
validate - Validate file integrity
infer-dialect - Infer file dialect

Copy Files

Copy files from local or remote sources to a local destination:

# Copy a local file
fairspec file copy data.csv --to-path output.csv

# Copy a remote file
fairspec file copy https://example.com/data.csv --to-path local-data.csv

# Copy from a dataset resource
fairspec file copy --from-dataset dataset.json --from-resource users --to-path users.csv

Options

--to-path <path> (required) - Local output path
--from-dataset <path> - Load file from dataset descriptor
--from-resource <name> - Specify resource name from dataset
--silent - Suppress output messages
--debug - Show debug information
--json - Output as JSON

Describe Files

Get detailed information about a file including size, type, and checksums:

# Describe a local file
fairspec file describe data.csv

# Describe with specific hash type
fairspec file describe data.csv --hash-type sha256

# Describe a remote file
fairspec file describe https://example.com/data.csv

# Describe from a dataset
fairspec file describe --from-dataset dataset.json --from-resource users

Output

The describe command returns:

bytes - File size in bytes
textual - Whether the file is text-based
integrity - Hash value and type

Options

--hash-type <type> - Hash algorithm to use
- Choices: md5, sha1, sha256 (default), sha512
--from-dataset <path> - Load file from dataset descriptor
--from-resource <name> - Specify resource name from dataset
--silent - Suppress output messages
--debug - Show debug information
--json - Output as JSON

Example Output

{
  "bytes": 1024,
  "textual": true,
  "integrity": {
    "type": "sha256",
    "hash": "a1b2c3d4e5f6..."
  }
}

Validate Files

Validate file integrity using checksums:

# Validate with expected hash
fairspec file validate data.csv --hash a1b2c3d4e5f6 --hash-type sha256

# Validate using MD5
fairspec file validate data.csv --hash 098f6bcd4621 --hash-type md5

# Output as JSON for automation
fairspec file validate data.csv --hash a1b2c3d4 --json

Options

--hash <hash> - Expected file hash
--hash-type <type> - Hash algorithm to use (default: md5)
- Choices: md5, sha1, sha256, sha512
--silent - Suppress output messages
--debug - Show debug information
--json - Output as JSON

Validation Report

Returns a validation report with:

valid - Boolean indicating if validation passed
errors - Array of validation errors (if any)

Example error:

{
  "valid": false,
  "errors": [
    {
      "type": "file/integrity",
      "hashType": "sha256",
      "expectedHash": "a1b2c3d4e5f6...",
      "actualHash": "different..."
    }
  ]
}

Infer File Dialect

Automatically detect the dialect of a file:

# Infer dialect from file
fairspec file infer-dialect data.csv

# Infer from remote file
fairspec file infer-dialect https://example.com/data.json

# Output as JSON
fairspec file infer-dialect data.xlsx --json

Options

--silent - Suppress output messages
--debug - Show debug information
--json - Output as JSON

Supported Formats

The command can detect:

CSV/TSV files
JSON/JSONL files
Excel files (.xlsx, .xls)
OpenDocument Spreadsheet (.ods)
Parquet files
Arrow/Feather files
SQLite databases

Working with Datasets

All file commands support loading files from dataset descriptors:

# Describe a resource from a dataset
fairspec file describe --from-dataset dataset.json --from-resource sales-data

# Copy a resource from a dataset
fairspec file copy --from-dataset dataset.json --from-resource users --to-path users.csv

# Validate a resource from a dataset
fairspec file validate --from-dataset dataset.json --from-resource products --hash abc123

Output Formats

Text Output (default)

Human-readable output with colors and formatting:

fairspec file describe data.csv

JSON Output

Machine-readable JSON for automation and scripting:

fairspec file describe data.csv --json

Silent Mode

Suppress all output except errors:

fairspec file copy data.csv --to-path output.csv --silent

Examples

Copy and Validate

# Copy a file and get its hash
fairspec file copy remote-data.csv --to-path local-data.csv
fairspec file describe local-data.csv --hash-type sha256

# Validate the copied file
fairspec file validate local-data.csv --hash <hash-from-describe> --hash-type sha256

Process Dataset Resources

# Describe all details of a dataset resource
fairspec file describe --from-dataset dataset.json --from-resource sales

# Copy the resource locally
fairspec file copy --from-dataset dataset.json --from-resource sales --to-path sales.csv

# Infer its dialect
fairspec file infer-dialect sales.csv

Automation with JSON

# Get file info as JSON for scripting
INFO=$(fairspec file describe data.csv --json)
HASH=$(echo $INFO | jq -r '.integrity.hash')

# Use in validation
fairspec file validate data.csv --hash $HASH --hash-type sha256

Search