data-exploration

Data Exploration with Dasel v3

<when_to_use>

Activate this skill when:

• Exploring unfamiliar structured data files (config, API responses, datasets)
• Discovering the schema or shape of a document before modifying it
• Investigating nested config structures (Kubernetes manifests, CI pipelines, package files)
• Sampling large arrays or deeply nested objects to understand content
• Identifying data types before transformation or extraction

</when_to_use>

Supported Formats

Dasel auto-detects format from file extension. Override with -i <format> when reading from stdin or when extension is ambiguous.

Format identifiers: json, yaml, toml, xml, csv, hcl, ini

Universal Exploration Workflow

Follow this sequence when encountering an unknown structured data file. Each step narrows scope.

Step 1 — Format Detection

Dasel infers format from file extension. For stdin or non-standard extensions, specify explicitly:

cat mystery_file | dasel -i json 'keys($this)'

Step 2 — Top-Level Keys

cat config.yaml | dasel -i yaml 'keys($this)'

Output: array of top-level key names. This is always the first exploration command.

Step 3 — Structure Preview

For small files (configs, manifests), dump the full document:

cat config.yaml | dasel -i yaml

For large files, skip to Step 4.

Step 4 — Nested Key Discovery

Navigate level by level:

cat config.yaml | dasel -i yaml 'server'
cat config.yaml | dasel -i yaml 'keys(server)'
cat config.yaml | dasel -i yaml 'keys(server.logging)'

Recursive key discovery across all depths:

cat config.yaml | dasel -i yaml '..keys($this)'

Step 5 — Array Sampling

Preview first few elements without loading entire array:

cat data.json | dasel -i json 'items[0:3]'

Single element inspection:

cat data.json | dasel -i json 'items[0]'

Step 6 — Type Inspection

Determine the type of any node:

cat data.json | dasel -i json 'typeOf(settings)'
cat data.json | dasel -i json 'typeOf(items[0].count)'