# Technical Documentation: TomWright/dasel

> ℹ️ **Provenance:** Multi-Tier Ingestion · [CodeWiki Reference](https://codewiki.google/github.com/TomWright/dasel)

### Overview (`README.md`)

[](https://daseldocs.tomwright.me)
[](https://goreportcard.com/report/github.com/tomwright/dasel/v3)
[](https://pkg.go.dev/github.com/tomwright/dasel/v3)


[](https://codecov.io/gh/TomWright/dasel)
[](https://github.com/avelino/awesome-go)



[](https://github.com/TomWright/dasel/releases/latest)
[](https://formulae.brew.sh/formula/dasel)

<div align="center">
    <img src="./daselgopher.png" alt="Dasel mascot" width="250"/>
</div>

# 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

* **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

### Homebrew (macOS/Linux)

```sh
brew install dasel
```

### Go Install

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

### Prebuilt Binaries

Prebuilt binaries are available on the [Releases](https://github.com/TomWright/dasel/releases) page for Linux, macOS, and Windows.

### None of the above?

See the [installation docs](https://daseldocs.tomwright.me/getting-started/installation) for more options.

---

## Shell Completion

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

```sh
# 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](https://daseldocs.tomwright.me/getting-started/shell-completion) for permanent installation instructions.

## Man Page

Generate and view the man page:

```sh
dasel man | man -l -
```

---

## Basic Usage

### Selecting Values

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

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

### Modifying Values

Update values inline:

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

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

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

Update values based on previous value:

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

### Format Conversion

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

### Recursive Descent (`..`)

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

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

```

### Search (`search`)

Finds all values matching a condition anywhere in the structure.

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

```

---

## Documentation

Full documentation is available at [daseldocs.tomwright.me](https://daseldocs.tomwright.me).

---

## Contributing

Contributions are welcome! Please see the [CONTRIBUTING.md](./CONTRIBUTING.md) for details.

---

## License

MIT License. See [LICENSE](./LICENSE) for details.

## Stargazers over time

[](https://starchart.cc/TomWright/dasel)

---

### Overview (`execution/README.md`)

# Execution

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

---

### Overview (`model/README.md`)

# 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`)

# Selector

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

---

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