duti Provider

Uses duti to manage “which app opens which file type” on macOS. Want every .md to open in VS Code, every .ts in Cursor, every image in IINA? That’s what this provider is for.

Platforms: macOS only

Usage


# Make VS Code the default for TypeScript files
hams duti set com.microsoft.VSCode public.typescript editor
 
# See what's managed
hams duti list
 
# Undo (reverts to system default)
hams duti unset com.microsoft.VSCode public.typescript editor

Three positional arguments: the app’s bundle ID, the UTI (file type), and the role (viewer / editor / shell / all).

Hamsfile example


# macOS/duti.hams.yaml
schema_version: 1
provider: duti
 
groups:
  - tag: code
    items:
      - urn: "urn:hams:duti:vscode-ts"
        step: Open TypeScript files with VS Code
        bundle_id: com.microsoft.VSCode
        uti: public.typescript
        role: editor
 
      - urn: "urn:hams:duti:vscode-md"
        step: Open Markdown with VS Code
        bundle_id: com.microsoft.VSCode
        uti: net.daringfireball.markdown
        role: editor
 
  - tag: media
    items:
      - urn: "urn:hams:duti:iina-video"
        step: Open video with IINA
        bundle_id: com.colliderli.iina
        uti: public.movie
        role: viewer

Common UTIs

File type	UTI
Markdown	`net.daringfireball.markdown`
TypeScript	`public.typescript`
JavaScript	`com.netscape.javascript-source`
JSON	`public.json`
Image (generic)	`public.image`
Video (generic)	`public.movie`
PDF	`com.adobe.pdf`
Plain text	`public.plain-text`

Want to know the UTI for a specific extension? duti -x md will tell you.

Finding an app’s bundle ID


# VS Code, for example
osascript -e 'id of app "Visual Studio Code"'
# com.microsoft.VSCode
 
# Or with mdls
mdls -name kMDItemCFBundleIdentifier /Applications/Visual\ Studio\ Code.app

How state is probed

For each entry, hams runs duti -x <ext> or duti -d <uti> to see which app macOS currently associates with that type, and compares against the Hamsfile’s bundle_id.

Bootstrap

Fresh Mac without duti? hams can install it for you via Homebrew. Pass --bootstrap to apply and hams runs brew install duti under your consent:


hams apply --bootstrap --from-repo=you/hams-store

On an interactive terminal without the flag, hams shows the exact command and asks [y/N/s]. See hams apply → About the bootstrap prompt for details. brew itself is also consent-gated — the fresh-Mac chain brew → duti can resolve in one hams apply --bootstrap call.

Or declare duti under Homebrew in the usual way:


# Homebrew.hams.yaml
- app: duti
  intro: Set default applications for file types.

duti writes to the Launch Services database. Sometimes new associations only take effect after restarting Finder or logging out and back in. If apply finishes but nothing seems to change, a quick logout/login usually sorts it.