dasel Documentation

Technical Documentation: TomWright/dasel

ℹ️ Provenance: Multi-Tier Ingestion · CodeWiki Reference

Overview (`README.md`) Copy Section

Dasel

Dasel (short for Data-Select) is a command-line tool and library for querying, modifying, and transforming data structures such as JSON, YAML, TOML, XML, CSV, and KDL.

It provides a consistent, powerful syntax to traverse and update data — making it useful for developers, DevOps, and data wrangling tasks.

Features Copy Chapter

• Multi-format support: JSON, YAML, TOML, XML, CSV, HCL, INI, KDL.
• Unified query syntax: Access data in any format with the same selectors.
• Query & search: Extract values, lists, or structures with intuitive syntax.
• Modify in place: Update, insert, or delete values directly in structured files.
• Convert between formats: Seamlessly transform data from JSON → YAML, TOML → JSON, etc.
• Script-friendly: Simple CLI integration for shell scripts and pipelines.
• Library support: Import and use in Go projects.

Installation Copy Chapter

Homebrew (macOS/Linux) Copy Section

brew install dasel

Go Install Copy Section

go install github.com/tomwright/dasel/v3/cmd/dasel@master

Prebuilt Binaries Copy Section

Prebuilt binaries are available on the Releases page for Linux, macOS, and Windows.

None of the above? Copy Section

See the installation docs for more options.

Shell Completion Copy Chapter

Dasel supports tab-completion for Bash, Zsh, Fish, and PowerShell. Generate and load the completion script for your shell:

# Bash
source <(dasel completion bash)

# Zsh
source <(dasel completion zsh)

# Fish
dasel completion fish | source

# PowerShell
dasel completion powershell | Out-String | Invoke-Expression

See the shell completion docs for permanent installation instructions.

Man Page Copy Chapter

Generate and view the man page:

dasel man | man -l -

Basic Usage Copy Chapter

Selecting Values Copy Section

By default, Dasel evaluates the final selector and prints the result.

echo '{"foo": {"bar": "baz"}}' | dasel -i json 'foo.bar'
# Output: "baz"

Modifying Values Copy Section

Update values inline:

echo '{"foo": {"bar": "baz"}}' | dasel -i json 'foo.bar = "bong"'
# Output: "bong"

Use --root to output the full document after modification:

echo '{"foo": {"bar": "baz"}}' | dasel -i json --root 'foo.bar = "bong"'
# Output:
{
  "foo": {
    "bar": "bong"
  }
}

Update values based on previous value:

echo '[1,2,3,4,5]' | dasel -i json --root 'each($this = $this*2)'
# Output:
[
    2,
    4,
    6,
    8,
    10
]

Format Conversion Copy Section

cat data.json | dasel -i json -o yaml

Recursive Descent (`..`) Copy Section

Searches all nested objects and arrays for a matching key or index.

echo '{"foo": {"bar": "baz"}}' | dasel -i json '..bar'
# Output:
[
    "baz"
]

Search (`search`) Copy Section

Finds all values matching a condition anywhere in the structure.

echo '{"foo": {"bar": "baz"}}' | dasel -i json 'search(bar == "baz")'
# Output:
[
    {
        "bar": "baz"
    }
]

Documentation Copy Chapter

Full documentation is available at daseldocs.tomwright.me.

Contributing Copy Chapter

Contributions are welcome! Please see the CONTRIBUTING.md for details.

License Copy Chapter

MIT License. See LICENSE for details.

Stargazers over time Copy Chapter

Overview (`execution/README.md`) Copy Section

Execution

The execution package accepts a model.Value, parses a selector and executes the resulting AST on the value.

Overview (`model/README.md`) Copy Section

Model

The model package contains the Value struct and functionality for the application.

model.Value is just a wrapper around reflect.Value but provides some additional logic for easier use.

Overview (`selector/README.md`) Copy Section

Selector

The selector package contains everything needed to parse a selector string into an AST, which we can then execute.

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