# 2618 Research Dasel CLI 8c667f38 > Dasel CLI Tool - Research Findings - Skill: `tools-only/2618-research-dasel-cli-8c667f38` (Agent Skill, multi-file: 3 files) - Install (CLI): `npx skillmds@latest add tools-only/2618-research-dasel-cli-8c667f38` - Raw SKILL.md: https://api.skillmd.com/api/skills/tools-only/2618-research-dasel-cli-8c667f38/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Research & Search - Author: tools-only (https://skillmd.com/u/tools-only) - Updated: 2026-09-22 - Page: https://skillmd.com/skills/tools-only/2618-research-dasel-cli-8c667f38 --- # Dasel CLI Tool - Research Findings ## What Dasel Is and What Problem It Solves Dasel (Data-Select) is a single-binary CLI tool and Go library for querying, modifying, and transforming structured data files. It solves the problem of needing separate tools (`jq` for JSON, `yq` for YAML, `xmllint` for XML) by providing one unified query syntax that works across all supported formats. Primary use cases: - Query values from structured config/data files in shell scripts - Modify structured data files in-place without full-language scripts - Convert between data formats (JSON to YAML, TOML to JSON, etc.) - Recursive search through nested documents Current stable version: **v3.2.2** (released 2026-02-13). v3 is a major rewrite with revised syntax. SOURCES: - README: (fetched 2026-02-19) - Docs: (fetched 2026-02-19) - Releases: (fetched 2026-02-19) - CHANGELOG: (fetched 2026-02-19) --- ## Supported Data Formats Confirmed from `cmd/dasel/main.go` import list and documentation: - JSON (`json`) - YAML (`yaml`) - TOML (`toml`) - XML (`xml`) - CSV (`csv`) - HCL (`hcl`) — added in v3.0.0 - INI (`ini`) — added in v3.0.0 Format identifiers (used with `-i`/`-o` flags): `json`, `yaml`, `toml`, `xml`, `csv`, `hcl`, `ini` --- ## Binary Release URL Pattern Base URL pattern: ```text https://github.com/TomWright/dasel/releases/download/v{VERSION}/dasel_{platform} ``` ### Available Platforms (v3.2.2, 18 assets total) | Asset Name | Platform | Notes | |---|---|---| | `dasel_linux_amd64` | Linux x86_64 | Primary Linux target | | `dasel_linux_amd64.gz` | Linux x86_64 compressed | | | `dasel_linux_arm64` | Linux ARM64 | | | `dasel_linux_arm64.gz` | Linux ARM64 compressed | | | `dasel_linux_arm32` | Linux ARM32 | | | `dasel_linux_arm32.gz` | Linux ARM32 compressed | | | `dasel_linux_386` | Linux x86 32-bit | | | `dasel_linux_386.gz` | Linux x86 32-bit compressed | | | `dasel_darwin_amd64` | macOS Intel | | | `dasel_darwin_amd64.gz` | macOS Intel compressed | | | `dasel_darwin_arm64` | macOS Apple Silicon | | | `dasel_darwin_arm64.gz` | macOS Apple Silicon compressed | | | `dasel_windows_amd64.exe` | Windows x64 | | | `dasel_windows_amd64.exe.gz` | Windows x64 compressed | | | `dasel_windows_386.exe` | Windows 32-bit | | | `dasel_windows_386.exe.gz` | Windows 32-bit compressed | | ### Concrete Examples (v3.2.2) ```text https://github.com/TomWright/dasel/releases/download/v3.2.2/dasel_linux_amd64 https://github.com/TomWright/dasel/releases/download/v3.2.2/dasel_linux_arm64 https://github.com/TomWright/dasel/releases/download/v3.2.2/dasel_windows_amd64.exe https://github.com/TomWright/dasel/releases/download/v3.2.2/dasel_darwin_arm64 ``` --- ## Checksum Verification Checksums are embedded directly in the GitHub release page per-asset. There is **no separate SHA256SUMS file** in releases. Each asset listing shows its sha256 hash inline. Observed sha256 values for v3.2.2: ```text dasel_linux_amd64: 313f055bd8c7c59bb8a9cad863f0685769d6f8a93b5f9b9a0986c95c76513832 dasel_linux_arm64: 135ac22a599fca49d48af44bd5dfa83bccdd91cd813c34c018e3574f76e842e6 dasel_linux_arm32: 6c43ff668c8205465e5509f94f39095d1ba86275e2e9d2d85976abe4c0cf1083 dasel_linux_386: 06c4024d39494ea46bff086ff3622cb2e8a722c3f68b604fa0cf6cf03365e887 dasel_darwin_amd64: cb064c256cc33e90ddc0630935bf6c6d640a34cf07eed5a47fdd365c13514239 dasel_darwin_arm64: 03f90053514080d57ed29b8558829e7e51f5ef8e62f25aa0029f67d2a9050e39 dasel_windows_amd64: bf5ccd37700525f7b55592064cb74fa7fae3d86b76f8a7b7fc7ef2c237c9c2c0 dasel_windows_386: 299ae7e3c889f13f9e26ee323c50cb6a3395284b7d625c9c2fc43e1695d1c87f ``` To verify after download: ```bash echo "313f055bd8c7c59bb8a9cad863f0685769d6f8a93b5f9b9a0986c95c76513832 dasel" | sha256sum -c ``` Checksums per release can be fetched dynamically via GitHub API: ```bash curl -s https://api.github.com/repos/tomwright/dasel/releases/latest \ | grep -E '"browser_download_url"|"sha256"' ``` --- ## Version Detection Command ```bash dasel --version ``` To get the latest available version from GitHub API: ```bash curl -s https://api.github.com/repos/tomwright/dasel/releases/latest \ | grep '"tag_name"' \ | cut -d'"' -f4 ``` --- ## Install Instructions ### Linux (64-bit amd64) — Auto-detect latest ```bash curl -sSLf "$(curl -sSLf https://api.github.com/repos/tomwright/dasel/releases/latest \ | grep browser_download_url \ | grep linux_amd64 \ | grep -v .gz \ | cut -d'"' -f4)" -L -o dasel && chmod +x dasel mv ./dasel /usr/local/bin/dasel ``` ### Linux (manual, pinned version) ```bash VERSION=v3.2.2 ARCH=linux_amd64 # or linux_arm64, linux_arm32, linux_386 curl -sSLf "https://github.com/TomWright/dasel/releases/download/${VERSION}/dasel_${ARCH}" \ -o /usr/local/bin/dasel chmod +x /usr/local/bin/dasel ``` ### Windows (PowerShell) ```powershell $releases = curl -sSLf https://api.github.com/repos/tomwright/dasel/releases/latest Invoke-WebRequest -Uri (($releases | ConvertFrom-Json).assets ` | Where-Object { $_.name -eq "dasel_windows_amd64.exe" } ` | Select-Object -ExpandProperty browser_download_url) ` -OutFile dasel.exe ``` ### Other install methods - Homebrew (macOS/Linux): `brew install dasel` - Docker: `docker run -i --rm ghcr.io/tomwright/dasel:latest` - Go: `go install github.com/tomwright/dasel/v3/cmd/dasel@master` - Scoop (Windows): `scoop bucket add extras && scoop install dasel` - ASDF: `asdf plugin add dasel && asdf install dasel ` - Mise: `mise install dasel@` - Nix: `nix-env -iA nixpkgs.dasel` --- ## Core CLI Syntax (v3) ### Flags ```text dasel [flags] [QUERY] Key flags: -f, --file Input file path (reads stdin if omitted) -i, --input Input parser: json, yaml, toml, xml, csv, hcl, ini -o, --output Output parser (defaults to input format) --root Output the full document after modification -w, --write Write result to file (modifies in-place if same as -f) --var = Pass variables into query (repeatable) --compact Compact output (no pretty-printing) --colour Enable colourised output --indent Set indentation string ``` ### Select (Query) — Read a Value ```bash # From piped stdin echo '{"foo": {"bar": "baz"}}' | dasel -i json 'foo.bar' # Output: "baz" # From file dasel -f data.json 'foo.bar' dasel -f config.yaml 'database.host' dasel -f data.toml 'server.port' ``` ### Modify in Place — Write a Value In v3, `put` and `delete` subcommands were removed. Modifications use assignment expressions with `--root` to output the full document: ```bash # Update a value and output full document echo '{"foo": {"bar": "baz"}}' | dasel -i json --root 'foo.bar = "newvalue"' # Modify file in place dasel -f config.yaml --root 'server.port = 9090' > config_new.yaml # Numeric assignment echo '{"count": 1}' | dasel -i json --root 'count = 42' # Boolean assignment echo '{"enabled": false}' | dasel -i json --root 'enabled = true' ``` ### Delete a Field In v3, deletion is done by constructing a new object/map without the unwanted key: ```bash # Remove a key using map spread (keeping all except the deleted key) # Build new object without 'unwanted_key': echo '{"keep": "yes", "remove": "no"}' | dasel -i json --root \ '{ keep }' ``` ### Array Operations ```bash # Access by index (zero-based) echo '[10, 20, 30]' | dasel -i json '[1]' # Output: 20 # Access last element echo '[10, 20, 30]' | dasel -i json '[len($this)-1]' # Range slice [start:end] echo '[1,2,3,4,5]' | dasel -i json '[0:2]' # Output: [1, 2, 3] # Append to array echo '[1,2,3]' | dasel -i json --root '[$this..., 4]' # Output: [1, 2, 3, 4] ``` ### Batch Modify Array Elements — `each` ```bash # Multiply all numbers by 2 echo '[1,2,3,4,5]' | dasel -i json --root 'each($this = $this*2)' # Output: [2, 4, 6, 8, 10] # Increment all integers echo '[1,2,3]' | dasel -i json 'each($this = $this+1)' ``` ### Format Conversion ```bash # JSON to YAML cat data.json | dasel -i json -o yaml # YAML to TOML cat config.yaml | dasel -i yaml -o toml # JSON to XML cat data.json | dasel -i json -o xml ``` ### Recursive Descent (`..`) ```bash # Find all values with key "name" at any depth echo '{"user": {"name": "Alice"}}' | dasel -i json '..name' # Output: ["Alice"] # Get first element of every nested array dasel -f data.json '..[0]' # Get all values at any depth dasel -f data.json '..*' ``` ### Search Function More powerful than `..` — supports arbitrary predicates: ```bash # Find all objects that have a "name" key dasel -f data.json 'search(has("name"))' # Find nodes where value equals 42 dasel -f data.json 'search($this == 42)' # Combined predicate dasel -f data.json 'search(has("id") && has("name"))' ``` ### Filter and Map ```bash # Filter array where active == true echo '...' | dasel -i json 'users.filter(active == true)' # Map: extract single field from array of objects echo '...' | dasel -i json 'users.map(name)' # Map with transformation echo '[1,2,3]' | dasel -i json '[1,2,3].map($this * 2)' ``` ### Conditionals ```bash # if/else expression dasel -i json -f input.json '.foo.if(bar == "baz") { bong } else { qux }' # Conditional with literal output echo '{ "count": 7 }' | dasel -i json 'if(count > 5) { "many" } else { "few" }' ``` ### Variable Assignment (v3 feature) ```bash # Multi-statement query with variables dasel -f data.json '$activeUsers = users.filter(active == true); $activeUsers.map(name)' ``` ### Type Casting Functions ```bash # typeOf: get type as string echo '"hello"' | dasel -i json 'typeOf($this)' # Output: "string" # toString: convert to string echo '123' | dasel -i json 'toString($this)' # Output: "123" # toInt: convert to integer echo '"42"' | dasel -i json 'toInt($this)' # Output: 42 # toFloat: convert to float echo '"3.14"' | dasel -i json 'toFloat($this)' ``` Type strings returned by `typeOf`: `"string"`, `"array"`, `"bool"`, `"null"`, `"int"`, `"float"` ### Other Useful Functions ```bash # len: length of array or string echo '[1,2,3]' | dasel -i json 'len($this)' # Output: 3 # has: check key/index exists (returns bool) echo '{"foo": "bar"}' | dasel -i json 'has("foo")' # Output: true # join: join array elements into string echo '["a","b","c"]' | dasel -i json 'join(",")' # Output: "a,b,c" # sum: sum numeric array echo '[1,2,3,4,5]' | dasel -i json 'sum($this)' # Output: 15 # keys: get map keys as array echo '{"a": 1, "b": 2}' | dasel -i json 'keys($this)' # reverse: reverse an array echo '[1,2,3]' | dasel -i json 'reverse($this)' ``` --- ## v3 Breaking Changes from v2 (Important) From CHANGELOG v3.0.0: - `put` and `delete` subcommands **removed**. Modifications done inline in query with `--root` flag. - Query/selector syntax **revamped** — v2 syntax is not compatible with v3. - Go module path changed to `github.com/tomwright/dasel/v3`. - CLI framework changed from Cobra to Kong. If a plugin needs to support v2 as well, the `put` command was used in v2: ```bash # v2 syntax (NOT v3): dasel put string -f data.json -o - '.foo.bar' 'newvalue' dasel delete -f data.json '.foo.bar' ``` --- ## Special Syntax Notes ### $root and $this Variables - `$root` — references the root document - `$this` — references the current node (used inside `each`, `map`, `filter`, `search`) ### Spread Operator ```bash # Spread array into arguments doSomething([1, 2, 3]...) # equivalent to doSomething(1, 2, 3) # Merge objects { {"firstName": "Tom"}..., "lastName": "Wright" } # resolves to { "firstName": "Tom", "lastName": "Wright" } # Output array elements as separate documents [1, 2, 3]... # 1 # 2 # 3 ``` ### Multi-statement Queries (semicolon separator) ```bash # Statements separated by semicolons; final statement is output dasel -f data.json '$active = users.filter(active == true); $active.map(name)' ``` ### Comments in Queries v3 supports comments in multi-statement queries (syntax not yet documented in official docs but noted in v3.0.0 release notes). --- ## References 1. README (raw): (fetched 2026-02-19) 2. Installation docs: (fetched 2026-02-19) 3. Releases page: (fetched 2026-02-19) 4. Release v3.2.2 assets: (fetched 2026-02-19) 5. CHANGELOG: (fetched 2026-02-19) 6. Query syntax docs: (fetched 2026-02-19) 7. Types/Literals: (fetched 2026-02-19) 8. Recursive descent: (fetched 2026-02-19) 9. Arrays/slices: (fetched 2026-02-19) 10. Objects/maps: (fetched 2026-02-19) 11. Conditionals: (fetched 2026-02-19) 12. Spread: (fetched 2026-02-19) 13. Functions index: (fetched 2026-02-19) 14. search(): (fetched 2026-02-19) 15. each(): (fetched 2026-02-19) 16. filter(): (fetched 2026-02-19) 17. map(): (fetched 2026-02-19) 18. typeOf(): (fetched 2026-02-19) 19. toString(): (fetched 2026-02-19) 20. toInt(): (fetched 2026-02-19) 21. has(): (fetched 2026-02-19) 22. join(): (fetched 2026-02-19) 23. main.go (format parsers): (fetched 2026-02-19)